PHYS490: Nuclear Physics - Liverpool · 2020. 2. 28. · 1/23/2020 PHYS490 : Advanced Nuclear...

1/23/2020 PHYS490 : Advanced Nuclear Physics : E.S. Paul 1

PHYS490: Nuclear Physics


PHYS490: Schedule 2020 Lectures :

Wednesday 09:00 – 10:00 (CTH-LTD) Friday 11:00 – 13:00 (MATH-029) Lectures : weeks 1 – 9 Easter 10 - 12 Tutorials : weeks 2, 5, 8 and (11) Text Book : K.S. Krane (or LaTeX notes on VITAL)

Edward Paul ([email protected]) Oliver Lodge Lab. Room 411

mailto:[email protected]


PHYS490: Nuclear Physics...

Topics (Chapters) 1. Introduction to Nuclear Physics 2. Nucleon-Nucleon Force 3. Nuclear Behaviour 4. Forms of Mean Potential 5. Nuclear Deformation 6. Hybrid Models 7. Nuclear Excitations 8. Rotating Systems 9. Nuclei at Extremes of Spin


...PHYS490: Nuclear Physics

Topics (Chapters)

10. Nuclei at Extremes of Isospin 11. Nuclei at Extremes of Mass and Charge 12. Mesoscopic Systems 13. Nuclear Reactions 14. Nuclear Astrophysics 15. Neutrinoless Double Beta Decay 16. Phases of Nuclear Matter 17. Accelerators for Nuclear Physics (new) 18. Our Research Highlights

Lectures/Chapters

Some subject areas are longer than others

ORBIT assigns double/single lecture slots (randomly!)

Subjects do not easily map onto lecture slots

Themes/topics (VITAL) are labelled Chapters


Advanced Nuclear Physics

Chapter 1



1. Introduction to Nuclear Physics

What is Nuclear Physics..?

“The goal of modern Nuclear Physics is to unravel the fundamental properties of nuclei from their building blocks, protons and neutrons (nucleons), and ultimately to determine the emergent complexity from the underlying quark and gluon degrees of freedom of Quantum Chromodynamics (QCD), the fundamental theory of the strong nuclear force”

Quote from Nuclear Physics News International, Vol. 29, No. 2, 2019


…What is Nuclear Physics?

“The science of Nuclear Physics covers the study of the atomic nucleus, which is where the mass of the atom is concentrated. Unravelling the often complex, structure and behaviour of the nucleus, and its constituents, is key to understanding how the variety of matter we see all around us – and which underpins our own existence – is generated”

Quote from NuPECC (Nuclear Physics European Collaboration Committee) 2017 Long Range Plan

Warning - pre Brexit quote!


Nuclear Physics Questions

The majority of visible mass of the universe is made up of atomic nuclei that lie at the centre of atoms

Current nuclear physics research seeks to answer fundamental questions

• How do the laws of physics work when driven to the extremes?

• What are the fundamental constituents and fabric of the universe and how do they interact?

• How did the universe begin and how is it evolving?

• What is the nature of nuclear and hadronic matter?


What Are Nuclei?

“Atomic nuclei are hierarchical structures composed of positively charged protons and neutral neutrons, which themselves are made up of fundamental particles – quarks”

“These are held together by the so-called strong force, but two of the other fundamental forces, the weak interaction and the electromagnetic force, also play a part in mediating nuclear structure and behaviour”

Quote from NuPECC (Nuclear Physics European Collaboration Committee) 2017 Long Range Plan



Prehistory (400 BC)

This chart of Plato and Aristotle shows the relation of the four elements and their four qualities

A fifth element was ether or material of the heavens (dark matter in early cosmology !)

The chart was used for over 1000 years

Elements


In 1803, the English Chemist-Physicist John Dalton started using symbols to represent the atoms of different elements

He soon had a table of 21 elements and eventually 36

The number of protons defines an element

The Periodic Table (Mendeleev)


2019: Year Of The Periodic Table


2016: Four New Elements


nihonium (Nh), moscovium (Mc), tennessine (Ts), oganesson (Og)

Element Discovery


294Og

Element 119

“If you want to create the world’s next undiscovered element, number 119 in the periodic table, take a few milligrams of berkelium, a rare radioactive metal that can be made only in specialized nuclear reactors.

Bombard the sample with a beam of titanium ions, accelerated to around one-tenth the speed of light.

Keep this up for about a year, and be patient. Very patient. For every 10 quintillion (1018) titanium ions that slam into the berkelium target — roughly a year’s worth of beam time — the experiment will probably produce only one atom of element 119.”

Quote from Nature 2019


Element 120 !!!

Darmstadt (GSI) have one candidate event for the production of element 120

Possibly 299120

Formed by the fusion of a 54Cr nucleus (beam) with a 248Cm radioactive target

From Acta Physica Polonica 2019


Nuclear Jargon

An atomic nucleus has :

Z “protons”

N “neutrons”

A constituents or “nucleons” (A = Z + N)

Same Z : “isotope” (defines chemical “element”)

Same N : “isotone”

Same A : “isobar”

Specific (N,Z) : “nuclide”

Plot of nuclides (N,Z) : “Segre chart”


Nuclear Properties

Atomic mass unit (u): 1.66 x 10-27 kg = 931.5 MeV/c2

Proton mass: 1.007276 u Question: why?

Neutron mass: 1.008665 u

Nuclear magneton (μN): 5.05 x 10-27 J/T

Proton magnetic moment: +2.7928 μN

Neutron magnetic moment: -1.9128 μN Question: why?



Atomic and Nuclear Sizes

Radius: r = 1.2 A1/3 fm


More and More Nuclides

Segre Chart

Z

N


Discovery History

Today around 3000 nuclides have been observed

Only 284 are stable


Limits of Stable Nuclei


The Unique Nucleus

The nucleus is a unique ensemble of strongly interacting fermions: nucleons

Its large, yet finite, number of constituents controls

the physics Both single-particle (out-of-phase) and collective

(in-phase) effects occur

Analogy to a herd of wild animals. Individual animals may break out of the herd but are rapidly drawn back to the safety of the collective


Nuclear Models

Quantum mechanics governs basic nuclear behaviour

The forces are complicated and cannot be written down explicitly

It is a many-body problem of great complexity

In the absence of a comprehensive nuclear theory we turn to models

A model is simply a way of looking at the nucleus that gives a physical insight into a wide range of its properties


Nuclear Physics in the 1930s

Cockcroft-Walton accelerator (DC) – nucleus ‘split’ in 1932



The first cyclotrons (AC) were built in Berkeley, California

Oliver Lodge Lab. Opening (1969)




An Open University program from 1979, shot in the Liverpool Physics Department, showing the forefront of nuclear structure experimentation - and fashion!

Also on youtube: http://youtu.be/s43rxUA8euY and VITAL

http://youtu.be/s43rxUA8euY



TESSA3: 16 (small) γ-ray detectors at Daresbury, UK


Even Bigger Detector Arrays

This picture shows ESSA30, an array of 30 (small) γ-ray detectors at Daresbury, UK

It was a European collaboration

Again, spot the Liverpudlians !



2003: The Hulk destroys Gammasphere !

Nuclear Physics Now


Ever more sensitive detector systems are being developed such as AGATA (Europe) and GRETA (USA)

They aim to make a highly efficient 4π germanium shell for the detection of γ rays


Nuclear Physics Tomorrow

The next generation of Radioactive Ion Beam (RIB) accelerators in Europe

Tools of Nuclear Physics

More details of the particle accelerators needed for Nuclear physics studies will be given later on in Chapter 17

Work in progress

ORBIT!


New Physics ?



Nuclear Physics In Context

Nuclear Physics is ‘the study of the structure, properties, and interactions of the atomic nuclei’

Nuclear Physicists investigate nuclear matter on all scales, from sub-atomic particles to supernovae

Research areas include the structure of the nucleus at different temperatures and pressures, the origin of elements, and the structure and evolution of stars

Why Study Nuclear Physics?

Since the discovery of the atomic nucleus just over a century ago, nuclear physics research and technology development has had a huge influence in Society’s everyday lives

Through energy production with low-carbon emission, radiation detection for national security or environmental monitoring, and cancer diagnosis and treatment in modern healthcare, the applications emerging from nuclear physics are numerous and yet very much relevant to today’s general public needs


Medical Applications

Historically, nuclear physics has made important contributions to applied science for the benefit of society

The first accelerators were developed to study nuclear phenomena and more recently they are employed in proton and carbon beam cancer therapy

Many of the detection systems used for medical imaging also have their origins in nuclear physics research, for example SPECT, PET and MRI


Summary

Brief history of Nuclear Physics

Elements

Nucleus represents a unique finite quantum system of strongly interacting fermions

Nuclear Physics in context


Advanced Nuclear Physics

Edward Paul


PHYS490: Nuclear Physics - Liverpool · 2020. 2. 28. · 1/23/2020 PHYS490 : Advanced Nuclear...

Documents

Transcript of PHYS490: Nuclear Physics - Liverpool · 2020. 2. 28. · 1/23/2020 PHYS490 : Advanced Nuclear...