同步辐射光源ByVicSuller
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•DOUBLE BEND LATTICE FUNCTIONS
•Length (m)
•Proposed South East Advanced Light Source (2)
•Discovery of Electron •JJ Thompson •October 1897
•Accelerated Charge Radiation •Lienard •July 1898
•ELECTROMAGNETIC RADIATION
•Field lines from a stationary charge
2. Relativistic Doppler shift from the electron frame to the lab
•
factor 2g
Result:- Frequency further increases by
3. Relativistic forward focusing of the emission
•Betatron - CERAMIC •Synchrotron - GLASS
•Relativistic effects in Synchrotron Radiation
1. Contraction of the orbit in the electron frame
•
g
Result:- Orbit frequency increases by factor
•Typical Synchrotron Radiation Spectra
•NSLS-VUV
•APS •CAMD
•Typical Synchrotron Radiation Spectra 2
•APS •CAMD •VUV
•1st Generation Synchrotron Radiation Sources
•GEC(USA) electron accelerators 1946
•First attempt to Detect Synchrotron Radiation
•John Blewett 1947 – used a microwave receiver expecting •Harmonics of the orbit frequency (100 MHz) - nothing found!
•Field lines from an accelerated charge
•z
•Spatial distribution of radiation
•from a charge accelerated
•along the z axis
•x •y
•Acceleration by Induction - The Betatron
•photons/sec/mr/0.1% bandwidth
•is a numerical factor which essentially governs the shape of the spectrum.
•Synchrotron Radiation Spectra
•Examples of spectra produced by electron storage rings:-
•Originally built for some other purpose (1965 – 1975)
•2nd Generation Synchrotron Radiation Sources
•Dedicated, purpose designed (1975 – 1985)
•Some examples:-
•Radiation excitation and damping of oscillations
•Betatron oscillation
•Radiation
•Radiation excitation
•Dispersion
•Initial momentum
•Radiation loss •RF restores
•Minimum emittance of Chasman-Green lattice
•Theoretical Minimum Emittance lattice
•3rd Generation Synchrotron Radiation Sources
•Dedicated, high brightness, designed to include •Insertion Device Sources (1985 – 2005?)
•where B is the bending magnetic field.
•Synchrotron Radiation Spectral Flux Intensity
•When the radiation at a given wavelength is integrated over all angles of vertical emission the resultant Spectral Flux Intensity is given by
•acceleration
•Transformation between frames:- •tan q = g-1 sin f (1+b cos f )-1
•If f = 900 then q = g-1
Байду номын сангаас
•Relativistic effects in Synchrotron Radiation (cont)
• For protons to radiate equivalently in a 100m orbit
•
Energy = 3.7 TeV and magnetic field = 10 kT
•Synchrotron Radiation Features 1. Continuum source from IR to X-rays 2. Source in a clean UHV environment 3. High Intensity and Brightness • 4. Highly Polarized • 5. Stable & controllable pulsed characteristics
•Principle of Betatron Acceleration
•Cross section of a Betatron
•Steel
•Coil •Vacuum chamber
•Prediction of Energy loss by radiation •in an accelerator
•Iwanenko & Pomeranchuk June 1944
同步辐射光源ByVicSuller
•Crab Nebula - the first Synchrotron source observed??
•CAMD in Baton Rouge, LA
•Center for Advanced Microstructures and Devices
•Accelerator Synchrotron Radiation
•…highly attractive for research applications!!!
•Synchrotron Radiation Features
•The synchrotron radiation spectrum is described with reference to a characteristic (often called 'critical') wavelength lc, or photon energy ec
•Final momentum
•Radiation damping
•The equilibrium of the excitation and the damping of the betatron oscillations determines the emittance of the stored beam with the result:
•Synchrotron Radiation Brightness
•Notice that Brightness, as here defined, is often referred to as Brilliance, with an accompanying incorrect use of the term brightness for the Spectral Flux Density. It is best to avoid confusion by using the well established radiometric definitions as given here.
•First correct theory of Synchrotron Radiation
•Julian Schwinger 1947 – showed the importance of relativistic effects
•Light from the GE Synchrotron 1947
•Average Spectral Brightness =
•
is the vertically integrated flux, 2.36sx is the fwhm of the horizontal electron
beam size, 2.36sz is the fwhm of the vertical electron beam size, and 2.36sg/ is the
•Note that source Brightness as defined is anisotropic, the value depends on the source density distribution and on the observation angle. It is often more convenient to use, as a figure of merit, an average brightness which for dipole sources is defined
The emittance is determined by the behaviour of the dispersion and the horizontal betatron function within the bending magnets. The emittance is given by the lattice of the machine.
•Some examples:-
•APS at Argonne National Laboratory
•Trends in 3rd Generation Light Source Performance
•Proposed South East Advanced Light Source (1)
•
•
Result:- Frequency further increases by
factor 2pg
•Relativistic focusing of Synchrotron Radiation
•Electron frame •f
•Lab frame
•q •velocity b
•acceleration
• The effect of 3 relativistic processes upshifts the orbit frequency by
• ~g3
• For example 2 GeV electrons in a 100m orbit
•
orbit frequency 3 MHz
•
g = 3914 g3 =6.0 1010 100m 1.7 nm (0.7 keV)
fwhm of the photon emission angle in the vertical plane. The latter is a combination
of the electron beam vertical divergence and the photon emission angle thus
•Length (m)
•Proposed South East Advanced Light Source (2)
•Discovery of Electron •JJ Thompson •October 1897
•Accelerated Charge Radiation •Lienard •July 1898
•ELECTROMAGNETIC RADIATION
•Field lines from a stationary charge
2. Relativistic Doppler shift from the electron frame to the lab
•
factor 2g
Result:- Frequency further increases by
3. Relativistic forward focusing of the emission
•Betatron - CERAMIC •Synchrotron - GLASS
•Relativistic effects in Synchrotron Radiation
1. Contraction of the orbit in the electron frame
•
g
Result:- Orbit frequency increases by factor
•Typical Synchrotron Radiation Spectra
•NSLS-VUV
•APS •CAMD
•Typical Synchrotron Radiation Spectra 2
•APS •CAMD •VUV
•1st Generation Synchrotron Radiation Sources
•GEC(USA) electron accelerators 1946
•First attempt to Detect Synchrotron Radiation
•John Blewett 1947 – used a microwave receiver expecting •Harmonics of the orbit frequency (100 MHz) - nothing found!
•Field lines from an accelerated charge
•z
•Spatial distribution of radiation
•from a charge accelerated
•along the z axis
•x •y
•Acceleration by Induction - The Betatron
•photons/sec/mr/0.1% bandwidth
•is a numerical factor which essentially governs the shape of the spectrum.
•Synchrotron Radiation Spectra
•Examples of spectra produced by electron storage rings:-
•Originally built for some other purpose (1965 – 1975)
•2nd Generation Synchrotron Radiation Sources
•Dedicated, purpose designed (1975 – 1985)
•Some examples:-
•Radiation excitation and damping of oscillations
•Betatron oscillation
•Radiation
•Radiation excitation
•Dispersion
•Initial momentum
•Radiation loss •RF restores
•Minimum emittance of Chasman-Green lattice
•Theoretical Minimum Emittance lattice
•3rd Generation Synchrotron Radiation Sources
•Dedicated, high brightness, designed to include •Insertion Device Sources (1985 – 2005?)
•where B is the bending magnetic field.
•Synchrotron Radiation Spectral Flux Intensity
•When the radiation at a given wavelength is integrated over all angles of vertical emission the resultant Spectral Flux Intensity is given by
•acceleration
•Transformation between frames:- •tan q = g-1 sin f (1+b cos f )-1
•If f = 900 then q = g-1
Байду номын сангаас
•Relativistic effects in Synchrotron Radiation (cont)
• For protons to radiate equivalently in a 100m orbit
•
Energy = 3.7 TeV and magnetic field = 10 kT
•Synchrotron Radiation Features 1. Continuum source from IR to X-rays 2. Source in a clean UHV environment 3. High Intensity and Brightness • 4. Highly Polarized • 5. Stable & controllable pulsed characteristics
•Principle of Betatron Acceleration
•Cross section of a Betatron
•Steel
•Coil •Vacuum chamber
•Prediction of Energy loss by radiation •in an accelerator
•Iwanenko & Pomeranchuk June 1944
同步辐射光源ByVicSuller
•Crab Nebula - the first Synchrotron source observed??
•CAMD in Baton Rouge, LA
•Center for Advanced Microstructures and Devices
•Accelerator Synchrotron Radiation
•…highly attractive for research applications!!!
•Synchrotron Radiation Features
•The synchrotron radiation spectrum is described with reference to a characteristic (often called 'critical') wavelength lc, or photon energy ec
•Final momentum
•Radiation damping
•The equilibrium of the excitation and the damping of the betatron oscillations determines the emittance of the stored beam with the result:
•Synchrotron Radiation Brightness
•Notice that Brightness, as here defined, is often referred to as Brilliance, with an accompanying incorrect use of the term brightness for the Spectral Flux Density. It is best to avoid confusion by using the well established radiometric definitions as given here.
•First correct theory of Synchrotron Radiation
•Julian Schwinger 1947 – showed the importance of relativistic effects
•Light from the GE Synchrotron 1947
•Average Spectral Brightness =
•
is the vertically integrated flux, 2.36sx is the fwhm of the horizontal electron
beam size, 2.36sz is the fwhm of the vertical electron beam size, and 2.36sg/ is the
•Note that source Brightness as defined is anisotropic, the value depends on the source density distribution and on the observation angle. It is often more convenient to use, as a figure of merit, an average brightness which for dipole sources is defined
The emittance is determined by the behaviour of the dispersion and the horizontal betatron function within the bending magnets. The emittance is given by the lattice of the machine.
•Some examples:-
•APS at Argonne National Laboratory
•Trends in 3rd Generation Light Source Performance
•Proposed South East Advanced Light Source (1)
•
•
Result:- Frequency further increases by
factor 2pg
•Relativistic focusing of Synchrotron Radiation
•Electron frame •f
•Lab frame
•q •velocity b
•acceleration
• The effect of 3 relativistic processes upshifts the orbit frequency by
• ~g3
• For example 2 GeV electrons in a 100m orbit
•
orbit frequency 3 MHz
•
g = 3914 g3 =6.0 1010 100m 1.7 nm (0.7 keV)
fwhm of the photon emission angle in the vertical plane. The latter is a combination
of the electron beam vertical divergence and the photon emission angle thus