RadiationRadiation

Electron InteractionsElectron Interactions Electrons interact with charges Electrons interact with charges

in atoms.in atoms.• Electrons decelerateElectrons decelerate

This radiation is called This radiation is called bremsstrahlungbremsstrahlung• ““braking radiation”braking radiation”

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Beta RangeBeta Range The range of an The range of an

electron in matter electron in matter varies.varies.• Energy dependentEnergy dependent

• Material Material dependentdependent

The measure is The measure is often scaled to the often scaled to the density.density.

Ejected PhotonsEjected Photons Electron can be accelerated Electron can be accelerated

toward a metal target.toward a metal target.• Heated cathode to create Heated cathode to create

electronselectrons

• High voltage to get high High voltage to get high energy electronsenergy electrons

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X-RaysX-Rays The photons come of The photons come of

with a spectrum of with a spectrum of energy.energy.• Called x-raysCalled x-rays

• Maximum corresponds Maximum corresponds to potentialto potential

Peaks correspond to Peaks correspond to specific quantized specific quantized energies in an atom.energies in an atom.

Compton ScatteringCompton Scattering Photons scattering from atomic Photons scattering from atomic

electrons are described by the electrons are described by the Compton effect.Compton effect.• Conservation of energy and Conservation of energy and

momentummomentum

• Special relativitySpecial relativity

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Compton EffectCompton Effect The energy and momentum The energy and momentum

equations can be combined equations can be combined into one relationship.into one relationship.• Compton equationCompton equation

• Frequency or wavelengthFrequency or wavelength

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Compton EnergyCompton Energy The wavelength shift is The wavelength shift is

independent of energy.independent of energy.• Only angleOnly angle

The energy of the photon The energy of the photon depends on the angle.depends on the angle.• Max at 180Max at 180°°

Recoil angle for electron Recoil angle for electron related to photon energy related to photon energy transfertransfer• Small Small cot large cot large

• Recoil near 90Recoil near 90°°

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