Radiation#

Functions dealing with synchrotron radiation

Functions

`DipoleRadiation()`	Compute the radiation integrals in dipoles
`ElementRadiation()`	Compute the radiation integrals in dipoles
`ElossRadiation()`	Compute the radiation integrals in EnergyLoss elements
`FDW()`	calculate radiation diffusion matrix of a wiggler element.
`WigglerRadiation()`	Compute the radiation integrals in wigglers
`atdiffmat()`	quantumDiff Compute the radiation-diffusion matrix
`atdisable_6d()`	switches radiation and cavity off
`atenable_6d()`	switches RF and radiation on
`atenergy()`	Gets the lattice energy
`atgetU0()`	Computes Energy loss per turn in eV .
`atradoff()`	Obsolete: switches RF and radiation off
`atradon()`	Obsolete: switches RF and radiation on
`atsetenergy()`	sets the Energy field in all elements.
`attapering()`	Scale magnet strengths
`check_6d()`	Checks the presence of longitudinal motion in a lattice.
`check_radiation()`	Obsolete: check the radiation state of a ring
`findelemraddiffm()`
`findmpoleraddiffmatrix()`	calculate radiation diffusion matrix of a multipole element
`findthickmpoleraddiffm()`
`findthinmpoleraddiffm()`
`ohmienvelope()`	calculates equilibrium beam envelope in a
`quantumDiff()`	Compute the radiation-diffusion matrix
`thickmpoleraddiffm()`	FIND
`thinmpoleraddiffm()`	FIND

DipoleRadiation()#: Compute the radiation integrals in dipoles

ElementRadiation()#: - Compute the radiation integrals in dipoles

and quadrupoles

ElossRadiation(ring, lindata)#: Compute the radiation integrals in EnergyLoss elements

[i1,i2,i3,i4,i5] = ElossRadiation(ring,lindata)

RING Lattice structure

LINDATA Output of atlinopt for all lattice elements (not used)

FDW(elem, orbit_in, energy)#: calculate radiation diffusion matrix of a wiggler element.

diff=FDW(elem,orbit_in,energy)

ELEM: AT wiggler element

ORBIT_IN: input closed orbit

ENERGY: ring energy [GeV]

diff=FDW(elem,orbit_in)

takes energy from the ‘Energy’ field of the element

for use in Ohmi’s beam envelope formalism [1]

[1] K.Ohmi et al. Phys.Rev.E. Vol.49. (1994)

See also ohmienvelope()

WigglerRadiation(ring, lindata)#: Compute the radiation integrals in wigglers

[i1,i2,i3,i4,i5] = WigglerRadiation(ring,lindata)

RING Lattice structure

LINDATA Output of atlinopt for all lattice elements

WigglerRadiation computes the radiation integrals for all wigglers with

the following approximations:

- The self-induced dispersion is neglected in I4 and I5, but is is used as

a lower limit for the I5 contribution

I1, I2 are integrated analytically

I3 is integrated analytically for a single harmonic, numerically otherwise

atdiffmat(ring)#: quantumDiff Compute the radiation-diffusion matrix

[bcum,bs]=atdiffmat(ring)

RING: Closed ring AT structure, containing radiative elements and

RF cavity. Radiative elements are identified by a

PassMethod ending with ‘RadPass’.

BCUM: Cumulated diffusion matrix

BS: Cumulative diffusion matrix at the beginning of each element

[bcum,bs]=atdiffmat(ring,’orbit’,orbitin)

ORBITIN: Initial 6-D closed orbit.

In this mode, RING may be a section of a ring.

atdisable_6d(ring, cavipass, bendpass, quadpass)#: switches radiation and cavity off

[newring,radindex,cavindex] = atdisable_6d(ring,cavipass,bendpass,quadpass)

Changes passmethods to turn off cavities, radiation damping and all

elements acting on the particle momentum.

The default is to turn everything OFF.,

INPUTS:

1. RING initial AT structure

2. CAVIPASS pass method for cavities

‘’ makes no change,

‘auto’ sets’IdentityPass’ or ‘DriftPass’ depending of cavity length)

anything else is used as the new PassMethod.

3. BENDPASS pass method for bending magnets

‘’ makes no change,

‘auto’ substitutes ‘RadPass’ with ‘Pass’ in any method

anything else is used as the new PassMethod.

4. QUADPASS pass method for quadrupoles

‘’ makes no change,

‘auto’ substitutes ‘RadPass’ with ‘Pass’ in any method

anything else is used as the new PassMethod.

[…] = atdisable_6d(…[,keyword,value]…)

The following keywords trigger the processing of the following elements:

‘allpass’ Defines the default pass method for all elements not

explicitly specified. Replaces the following default

values.

‘cavipass’ pass method for RF cavities. Default ‘auto’

‘bendpass’ pass method for bending magnets. Default ‘auto’

‘quadpass’ pass method for quadrupoles. Default ‘auto’

‘sextupass’ pass method for sextupoles. Default ‘auto’

‘octupass’ pass method for bending magnets. Default ‘auto’

‘multipolepass’ pass method for multipole magnets. Default ‘auto’

‘wigglerpass’ pass method for wigglers. Default ‘auto’

‘quantdiffpass’ pass method for quantum diffusion. Default ‘auto’

‘energylosspass’ pass method for atenergyloss element. Default ‘auto’

‘simplequantdiffpass’ pass method for SimpleQuantDiff element. Default ‘auto’

‘simpleradiationpass’ pass method for SimpleRadiation element. Default ‘auto’

OUPUTS:

1. NEWRING Output ring

2. RADINDEX Indices of elements with radiation

3. CAVINDEX Indices of active cavities

EXAMPLES:

>> ringrad=atdisable_6d(ring);

Turns off all elements acting on momentum.

>> ringrad=atdisable_6d(ring,’auto’,’allpass’,’’);

Turns cavities off and leaves everything else unchanged.

>> ringrad=atdisable_6d(ring,’allpass’,’auto’,’cavipass’,’’);

Turns off everything except RF cavities.

See also atenable_6d(), check_6d(), atcavityon(), atcavityoff()

atenable_6d(ring, cavipass, bendpass, quadpass)#: switches RF and radiation on

[newring,radindex,cavindex] = atenable_6d(ring,cavipass,bendpass,quadpass)

Changes passmethods to get RF cavity acceleration and radiation

damping.

The default is to turn cavities ON and set radiation in dipoles,

quadrupoles and wigglers.

INPUTS:

1. RING initial AT structure

2. CAVIPASS pass method for cavities

‘’ makes no change,

‘auto’ set ‘RFCavityPass’,

anything else is used as the new PassMethod.

3. BENDPASS pass method for bending magnets

‘’ makes no change,

‘auto’ substitutes ‘Pass’ with ‘RadPass’ in any method,

anything else is used as the new PassMethod.

4. QUADPASS pass method for quadrupoles

‘’ makes no change,

‘auto’ substitutes ‘Pass’ with ‘RadPass’ in any method,

anything else is used as the new PassMethod.

[…] = atenable_6d(…,keyword,value)

The following keywords trigger the processing of the following elements:

‘allpass’ Defines the default pass method for all elements not

explicitly specified. Replaces the following default

values.

‘cavipass’ pass method for RF cavities. Default ‘auto’

‘bendpass’ pass method for bending magnets. Default ‘auto’

‘quadpass’ pass method for quadrupoles. Default ‘auto’

‘sextupass’ pass method for sextupoles. Default ‘’

‘octupass’ pass method for octupoles. Default ‘’

‘multipolepass’ pass method for multipole magnets. Default ‘’

‘wigglerpass’ pass method for wigglers. Default ‘auto’

‘quantdiffpass’ pass method for quantum radiation. default ‘auto’

‘energylosspass’ pass method for energyloss element. default ‘auto’

‘simplequantdiffpass’ pass method for SimpleQuantDiff element. Default ‘auto’

‘simpleradiationpass’ pass method for SimpleRadiation element. Default ‘auto’

OUPUTS:

1. NEWRING Output ring

2. RADINDEX Indices of elements with radiation

3. CAVINDEX Indices of active cavities

EXAMPLES:

>> ringrad=atenable_6d(ring);

Turns cavities on and sets radiation in bending magnets, quadrupoles, energyloss elements, and wigglers (default)

>> ringrad=atenable_6d(ring,’auto’,’allpass’,’’);

Turns cavities on and leaves everything else unchanged

>> ringrad=atenable_6d(ring,’allpass’,’’,’bendpass’,’auto’);

Turns on radiation in bending magnets and leaves everything else unchanged

See also atdisable_6d(), check_6d(), atcavityon(), atcavityoff()

atenergy(ring)#: Gets the lattice energy

energy=atenergy(ring)

[energy,periods]=atenergy(ring)

[energy,periods,voltage,harmnumber]=atenergy(ring)

[energy,periods,voltage,harmnumber,u0]=atenergy(ring)

Warning: To get ENERGY, PERIODS and HARMNUMBER, use atGetRingProperties

To get U0, use atgetU0

RING Ring structure

ENERGY Ring energy

atenergy looks for the machine energy in:

1) the 1st ‘RingParam’ element

2) the ‘RFCavity’ with the lowest frequency

3) the field “E0” of the global variable “GLOBVAL”

4) The field “Energy” in any element

PERIODS Number of periods

VOLTAGE Total RF voltage for the main cavities. The main cavities

are the ones with the lowest frequency

HARMNUMBER Harmonic number. Computed from the frequency of the main cavities

U0 Total energy loss per turn

See also atGetRingProperties(), atgetU0(), atsetcavity()

atgetU0(ring)#: Computes Energy loss per turn in eV .

u0=atgetU0(ring) Return the energy loss/turn in eV for the full ring.

RING: Ring structure

U0: Energy loss per turn in eV

u0=atgetU0(…,’periods’,periods) Select the number of periods

PERIODS if the number of periods to take into account (Default: full ring)

u0=atgetU0(…,’method’,method) Choose the method

METHOD: ‘integral’: (default) The losses are obtained from

Losses = Cgamma / 2pi * EGeV^4 * I2

Takes into account bending magnets and wigglers.

‘tracking’: The losses are obtained by tracking without cavities.

Needs radiation ON, takes into account all radiating elements.

See also ringpara(), atsetcavity(), atenergy()

atradoff()#: Obsolete: switches RF and radiation off

Kept for compatibility. The function name is misleading, because the

function acts not only on synchrotron radiation, but more generally on

all elements modifying the longitudinal momentum.

<a href=”matlab:help atdisable_6d”>atdisable_6d</a> is an exact copy of this function and should preferably be

used.

See also atdisable_6d(), atenable_6d(), check_6d(), atcavityoff(), atcavityon()

atradon()#: Obsolete: switches RF and radiation on

Kept for compatibility. The function name is misleading, because the

function acts not only on synchrotron radiation, but more generally on

all elements modifying the longitudinal momentum.

<a href=”matlab:help atenable_6d”>atenable_6d</a> is an exact copy of this function and should preferably be

used.

See also atenable_6d(), atdisable_6d(), check_6d(), atcavityon(), atcavityoff()

atsetenergy(ring, energy)#: sets the Energy field in all elements.

If no such field exists, it creates it.

newring = atsetenergy(ring,energy)

ring: an AT ring.

Energy: Value to set the Energy field. Units: eV

newring: new AT ring with Energy field set.

Example:

Set the energy of the elements in RING to 3 GeV.

newring = atsetenergy(ring,3e9)

See also atenergy()

attapering(ring)#: Scale magnet strengths

newring=attapering(ring) Scales dipole strengths with local energy to

cancel the closed orbit due to synchrotron radiation.

newring=attapering(ring,’multipoles’, true) Scales also the

multipoles to cancel optics errors. The default is true

newring=attapering(ring,’niter’,niter) Performs niter iterations (useful

when multipoles are scaled). Default 1

check_6d(ring) returns the radiation state of ring (true/false)#: Checks the presence of longitudinal motion in a lattice.

is_6d = check_6d(ring) returns the radiation state of ring (true/false).

Equivalent to IS_6D=<a href=”matlab:help atGetRingProperties”>atGetRingProperties</a>(RING,’is_6d’)

is_6d = check_6d(ring, enable)

Generates an error if IS_6D is different of ENABLE

[is_6d, newring] = check_6d(ring,enable,’force’)

The keyword ‘force’ overrides any error check, and converts

the RING according to the value of ENABLE.

IS_6D contains the status of the RING before conversion.

[is_6d, newring] = check_6d(ring,enable,’strict’,strict)

Default, STRICT=true.

If STRICT is true, a difference btw IS_6D and ENABLE produces an error.

If STRICT is false, a difference btw IS_6D and ENABLE produces a warning,

and the RING is converted according to the value of ENABLE.

IS_6D contains the status of the RING before conversion.

See also atGetRingProperties(), atenable_6d(), atdisable_6d()

check_radiation()#: Obsolete: check the radiation state of a ring

Kept for compatibility> The function name is misleading, because the

function checks not only the presence of synchrotron radiation, but more

generally of all elements modifying the longitudinal momentum.

<a href=”matlab:help check_6d”>check_6d</a> is an exact copy of this function and should preferably be

used.

See also check_6d(), atGetRingProperties(), atenable_6d(), atdisable_6d()

findelemraddiffm()#

findmpoleraddiffmatrix(elem, orbit_in, energy)#: calculate radiation diffusion matrix of a multipole element

diff=findmpoleraddiffmatrix(elem,orbit_in,energy)

ELEM: AT multipole element

ORBIT_IN: input closed orbit

ENERGY: ring energy [eV]

diff=findmpoleraddiffmatrix(elem,orbit_in)

takes energy from the ‘Energy’ field of the element

for use in Ohmi’s beam envelope formalism [1]

[1] K.Ohmi et al. Phys.Rev.E. Vol.49. (1994)

See also ohmienvelope()

findthickmpoleraddiffm()#

findthinmpoleraddiffm()#

ohmienvelope(ring, radelemindex)#: calculates equilibrium beam envelope in a

circular accelerator using Ohmi’s beam envelope formalism [1].

[1] K.Ohmi et al. Phys.Rev.E. Vol.49. (1994)

[envelope, rmsdp, rmsbl] = ohmienvelope(ring,radelemindex)

[envelope, rmsdp, rmsbl] = ohmienvelope(ring,radelemindex,refpts)

RING - an AT ring.

RADELEMINDEX - ignored, kept for compatibility

REFPTS - reference points along the ring. Default: 1

ENVELOPE is a structure with fields

Sigma - [SIGMA(1); SIGMA(2)] - RMS size [m] along

the principal axis of a tilted ellips

Assuming normal distribution exp(-(Z^2)/(2*SIGMA))

Tilt - Tilt angle of the XY ellipse [rad]

Positive Tilt corresponds to Corkscrew (right)

rotatiom of XY plane around s-axis

R - 6-by-6 equilibrium envelope matrix R

RMSDP - RMS momentum spread

RMSBL - RMS bunch length[m]

[envelope, rmsdp, rmsbl, m66, t, orbit] = ohmienvelope(…)

Returns in addition the 6x6 transfer matrices and the closed orbit

from FINDM66

See also atenable_6d(), findm66()

quantumDiff(ring)#: Compute the radiation-diffusion matrix

diffmat=quantumDiff(ring)

RING: Closed ring AT structure, containing radiative elements and

RF cavity. Radiative elements are identified by a

PassMethod ending with ‘RadPass’.

diffmat=quantumDiff(line,radindex,orbitin) (deprecated syntax)

diffmat=quantumDiff(…,’orbit’,orbitin)

RADINDEX: Ignored

ORBITIN: Initial 6-D closed orbit.

In this mode, LINE may be a section of a ring.

thickmpoleraddiffm()#: FIND

thinmpoleraddiffm()#: FIND