lecture 6 experimental nuclear physics phys...

Experimental Nuclear Physics - PHYS741Karsten Heeger, Univ. Wisconsin 76

Lecture 6

Experimental Nuclear Physics PHYS 741

[email protected]

References and Figures from:- Basdevant et al., “Fundamentals in Nuclear Physics”- Henley et al., “Subatomic Physics”

Experimental Nuclear Physics - PHYS741Karsten Heeger, Univ. Wisconsin

The Frontiers in Nuclear Science - A Long Range Plan

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http://lanl.arxiv.org/pdf/0809.3137

- provides good context for our field

- nice illustrations

- easy to browse through

will talk about major themes in this report next Monday, Sep 29

-> be prepared and read it


Course Projects• Assignment - The goal of the course project is to have you research a topic in nuclear physics research or related areas, discuss its physics motivation, and present its status and open questions to the class.

• Presentation- You will have about 20min for your presentation plus 5-10min of questions

and discussions. This corresponds to about 20 slides depending on how fast or slow you talk.

- Talks will be posted in electronic form on the course website. - Talks will be graded based on content, clarity of presentation and

explanation, background knowledge and discussion of particular topic within broader research context.

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Course ProjectsBy October 5

Pick three topics of interest from the list (ranked by preference) or define your own topic for the research project and email those to me. If more than one person is interested in a given subject, I will assign a topic based on your preferences.

By October 17 Establish a reading list of at least three readable references on the subject that is finally assigned to you, and go over the reading list with me so we agree on what you will read and research for the project.

By November 21 Prepare a conference-style presentation in PowerPoint, Keynote, PDF, or in some other electronic presentation format. Let me know if you do not have access to a computer to prepare the presentation. Email me the electronic file of your presentation so I can look it over.

November 24 - December 3 Arrange a time to meet with me to go over the draft presentation, and then refine your presentation based on our individual discussions.

December 5 (or some other day) Project presentations to the class. We will schedule an afternoon or evening with pizza to hear everyone’s presentation.

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Course ProjectsSome Electronic Resources and Archives

Preprint arXive http://arxiv.org/

SPIRES HEP http://www.slac.stanford.edu/spires/

Particle Data Group http://pdg.lbl.gov/

National Nuclear Data Center http://www.nndc.bnl.gov/

Department of Energy, Office of Science Nuclear Physicshttp://www.er.doe.gov/Program_Offices/NP.htm

University of Wisconsin, Physics Library http://physics.library.wisc.edu/

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Scattering Topics• scattering/cross-sections in QM (perturbation theory)

– elastic scattering– quasi-elastic scattering

• particle-particle scattering– two free particles– particles on bound particle (form factors)– scattering on charge distribution– electron - nucleus scattering– electron - nucleon scattering– resonances – nucleon-nucleus scattering– coherent scattering

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Non-Relativistic Particles in Yukawa Potential

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QM calculation

no divergence at small angles> we need QM

scattering follows Coulomb cross-section at large anglesYukawa=solid line

Coulomb=dashed line


Non-Relativistic Particles in Yukawa Potential

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particle penetration to about r0/10

Yukawa=solid lineCoulomb=dashed line

for b< r0 potential give nearly same result

for b >>r0 Yukawa scattering less than Coulomb scattering because.... ?

Yukawa force drops much faster with distance

classical calculation


Scattering of Single Particle

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scattering of particle on fixed potential

scattering of particle with recoil


Rutherford

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Mott Scattering

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Rutherford

Mott- relativistic electrons- nuclear recoil- magnetic moment

Hofstadter, R., et al., Phys. Rev. 92, 978 (1953).


Scattering of Particle in Bound State

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left in bound state ejected from bound state


Charge Distributions and Form Factors

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charge distributions form factor

form factors equal at low q

charge distributions have same mean square radius <r2>


Elastic Scattering of e- on Ca

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predicition of Mott scattering for heavy, spinless, point nucleus

data


Electron- C Scattering: Excited States of 12C

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elastic scattering

what happened to 2 MeV?

inelastic scattering-> excited state of nucleus


Electron-Deuteron Scattering

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elastic scattering

what happened to 40 MeV?

dissociation of deuteron- elastic scattering on either n or p- B(2,1) = 2.2 MeV-> recoiling nucleon inside nucleus -> width of inelastic peak = momentum distribution of nucleons inside nucleus


Electron-Proton Scattering

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pointlike proton

exponential charge distribution with mean radius


Charge and Magnetic Moment Densities of Protons and Neutrons

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Derived Charge and Magnetic Moment Densitiesproton: most charge within < 0.8 fm

neutron: positively charged core < 0.3fmsurrounded by neg charge 0.3-2fm

proton form factor - prediction for exponential charge distribution with mean charge radius of 0.8 fm- experimental data


Nucleon-Nucleus Scattering

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neutron emission

photon emissions

fission

Resonances, Elastic, Inelastic Scattering


Scattering of Waves on Target

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forward scattering


Ultracold Neutrons at ILL

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this could also be a topic for a course project


E158 Experiment at SLAC - Moller Scattering

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• http://www.slac.stanford.edu/exp/e158/

- first observation of Parity Violation in electron-electron (Møller) scattering

- measurement of weak electric charge

lecture 6 experimental nuclear physics phys...

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