Lecture 4 ½ The end of the SEMF 9 Nov 2005, Lecture 4.

Slides:

Advertisements

Similar presentations

Neutron Excess Asymmetry Remember HWc 1.

Advertisements

Nuclear Binding Energy

3224 Nuclear and Particle Physics Ruben Saakyan UCL

Isomer Spectroscopy in Near-Spherical Nuclei Lecture at the ‘School cum Workshop on Yrast and Near-Yrast Spectroscopy’ IIT Roorkee, October 2009 Paddy.

P461 - Nuclei I1 Properties of Nuclei Z protons and N neutrons held together with a short-ranged force  gives binding energy P and n made from quarks.

Nov 2006, Lecture 2 Nuclear Physics Lectures, Dr. Armin Reichold 1 Lecture 2 The Semi Empirical Mass Formula SEMF.

Radiogenic Isotope Geochemistry Lecture 29 Introduction & Physics of the Nucleus.

BASIC CONCEPTS.  Summary-1  The net nuclear charge in a nuclear species is equal to + Ze, where Z is the atomic number and e is the magnitude.

Nuclear Physics Nucleus: –nucleons (neutrons and protons) bound together. –Strong Force binds nucleons together over short range (~ m) –Nuclide:

PA 1140 Waves and Quanta Unit 4: Atoms and Nuclei l Lecture course slides can be seen at:

More About Decay Modes Nuclear Physics Lesson 9. Homework Revise for the skills test. Revise for the skills test. HWK days: HWK days: Tues Wk 1 Period.

Lecture 354/26/06. What does it mean to be radioactive? Radioactivity vs. nuclear power.

P461 - Nuclei II1 Nuclear Shell Model Potential between nucleons can be studied by studying bound states (pn, ppn, pnn, ppnn) or by scattering cross sections:

Nucleus. Nuclear Notation  The nucleus consists of protons and neutrons. Protons: Z (atomic number) Neutrons: N Nucleons: A = Z + N (atomic mass) Full.

X-rays Section 31-7 Physics 1161: Pre-Lecture 32.

11 Nov 2004, Lecture 3 Nuclear Physics Lectures, Dr. Armin Reichold 1 Lecture 3 Using the SEMF and realising its limitations.

Nuclear models. Models we will consider… Independent particle shell model Look at data that motivates the model Construct a model Make and test predictions.

Feedback from last 2 lectures

Physics 133: Extragalactic Astronomy and Cosmology Lecture 15; March

Radioactivity – types of decays presentation for April 28, 2008 by Dr. Brian Davies, WIU Physics Dept.

11 Nov 2004, Lecture 3 Nuclear Physics Lectures, Dr. Armin Reichold 1 Lecture 3 nuclear stability, decays and natural radioactivity.

NUCLEAR STRUCTURE PHENOMENOLOGICAL MODELS

CHEM 312: Lecture 2 Nuclear Properties

Nuclear and Radiation Physics, BAU, 1 st Semester, (Saed Dababneh). 1 Nuclear Binding Energy B tot (A,Z) = [ Zm H + Nm n - m(A,Z) ] c 2 B  m.

Fission and Fusion 3224 Nuclear and Particle Physics Ruben Saakyan UCL.

Nuclear and Radiation Physics, BAU, Second Semester, (Saed Dababneh) Nuclear and Radiation Physics Before we start, let us tackle.

Lecture 4 Nuclear Stability, The Shell Model. Nuclear Stability A sufficient condition for nuclear stability is that, for a collection of A nucleons,

NUCLEAR MODELS.

ELEMENTS atomic number = Z = number of protons = p mass number = number of nucleons = p + n atomic mass = experimental measurement of the mass of the.

Experimental evidence for closed nuclear shells Neutron Proton Deviations from Bethe-Weizsäcker mass formula: mass number A B/A (MeV per nucleon)

Nuclear Models Nuclear force is not yet fully understood.

Known nuclides PROPERTIES OF FUNDAMENTAL PARTICLES Particle Symbol Charge Mass (x Coulombs) (x kg) Proton P Neutron N.

Nuclear Physics PHY Outline  history  structure of the nucleus nuclear binding force liquid drop model shell model – magic numbers 

Lecture 1 & 2 © 2015 Calculate the mass defect and the binding energy per nucleon for a particular isotope.Calculate the mass defect and the binding.

& Average Atomic Mass  Atoms with the same number of protons (they are the same element) but different number of neutrons.

1-1 CHEM 312 Radiochemistry Lecture 1: Introduction Part 2 Readings: §Chart of the nuclides àClass handout §Table of the isotopes §Modern Nuclear Chemistry:

1-1 CHEM 312 Radiochemistry Lecture 1: Introduction Readings: §Chart of the nuclides àClass handout §Table of the isotopes §Modern Nuclear Chemistry: Chapter.

LLNL-PRES This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344.

The Shell Model of the Nucleus 1. Evidences [Sec. 5.1 and 5.2 Dunlap]

Radiochemistry Dr Nick Evans

Inorganic Chemistry May 12, Describe how the strong force attracts nucleons Relate binding energy and mass defect Predict the stability of a nucleus.

H.Sakurai Univ. of Tokyo Spectroscopy on light exotic nuclei.

Nuclear and Radiation Physics, BAU, 1 st Semester, (Saed Dababneh) Nuclear and Radiation Physics Why nuclear physics? Why radiation.

The Nuclear Shell Model A Review of The Nuclear Shell Model By Febdian Rusydi.

Prof. Paddy Regan Department of Physics

Oct 2006, Lectures 4&5 1 Lectures 4 & 5 The end of the SEMF and the nuclear shell model.

The Semi-empirical Mass Formula

Nuclear and Radiation Physics, BAU, First Semester, (Saed Dababneh) Nuclear and Radiation Physics Before we start, let us tackle.

Nuclear and Radiation Physics, BAU, 1 st Semester, (Saed Dababneh). 1 The Deuteron Deuterium (atom). The only bound state of two nucleons  simplest.

The Chart of Nuclei N=Z As size of nucleus increases, ratio N/Z increases because more neutrons needed to keep nucleus stable Just above stable region,

Nuclear Physics I Dr. Mohammed Hassen Abu-Sei’leek.

Nuclear Phenomenology 3C24 Nuclear and Particle Physics Tricia Vahle & Simon Dean (based on Lecture Notes from Ruben Saakyan) UCL.

X-rays Physics 102: Lecture 26 Make sure your grade book entries are correct.

Physics 102: Lecture 26, Slide 1 X-rays Today’s Lecture will cover Section 27.4 Physics 102: Lecture 26 Make sure your grade book entries are correct.

Nuclear Binding Energy

True or False Alpha is the least penetrating form of radiation

X-rays Physics 102: Lecture 26

gamma-transmission coefficients are most uncertain values !!!

Study of SHE at the GSI – SHIP

Properties of Nuclei Z protons and N neutrons held together with a short-ranged force  gives binding energy P and n made from quarks. Most of the mass.

Nuclear Stability.

Nuclear Physics, JU, Second Semester,

the nuclear force & the shell model

Parametrisation of Binding Energies

Symmetry energy coefficients and shell gaps from nuclear masses

Isotopes Atoms with SAME number of PROTONS (atomic number) but DIFFERENT numbers of neutrons (i.e. mass number) 6 protons 6 neutrons 6 protons 7 neutrons.

STRUCTURE OF ATOM AND NUCLEUS

Nuclear Physics PHY

More about Elements.

Find the average of the following numbers…

Presentation transcript:

Lecture 4 ½ The end of the SEMF 9 Nov 2005, Lecture 4

4.1 Overview 4.2 Shortcomings of the SEMF magic numbers for N and Z spin & parity of nuclei unexplained magnetic moments of nuclei value of nuclear density values of the SEMF coefficients 9 Nov 2005, Lecture 4

4.2 Shortcomings of the SEMF 9 Nov 2005, Lecture 4

4.2 Shortcomings of the SEMF (magic numbers in Ebind/A) SEMF does not apply for A<20 There are deviations from SEMF for A>20 (2,2) 2*(2,2) = Be(4,4) Ea-a=94keV (6,6) (8,8) (10,10) (N,Z) 9 Nov 2005, Lecture 4

N Z Neutron Magic Numbers 4.2 Shortcomings of the SEMF (magic numbers in numbers of stable isotopes and isotones) Proton Magic Numbers Magic Proton Numbers (stable isotopes) Magic Neutron Numbers (stable isotones) 9 Nov 2005, Lecture 4

4.2 Shortcomings of the SEMF (magic numbers in separation energies) Neutron separation energies saw tooth from pairing term step down when N goes across magic number at 82 Ba Neutron separation energy in MeV 9 Nov 2005, Lecture 4

4.2 Shortcomings of the SEMF (abundances of elements in the solar system) Z=50 N=82 Z=82 N=126 iron mountain Complex plot due to dynamics of creation, see lecture on nucleosynthesis no A=5 or 8 9 Nov 2005, Lecture 4

4.2 Shortcomings of the SEMF (other evidence for magic numbers) Nuclei with N=magic have abnormally small n-capture cross sections (they don’t like n’s) First excitation energy Close to magic numbers nuclei can have “long lived” excited states (tg>O(10-6 s) called “isomers”. One speaks of “islands of isomerism” [Don’t make holydays there!] 208Pb 9 Nov 2005, Lecture 4

4.2 Shortcomings of the SEMF (others) spin & parity of nuclei do not fit into a drop model magnetic moments of nuclei are incompatible with drops value of nuclear density is unpredicted values of the SEMF coefficients except Coulomb and Asymmetry are completely empirical 9 Nov 2005, Lecture 4

End of Lecture 4 9 Nov 2005, Lecture 4