xal.model.elem

Class IdealMagSectorDipole2

java.lang.Object

xal.model.elem.Element

xal.model.elem.ThickElement

xal.model.elem.ThickElectromagnet

xal.model.elem.IdealMagSectorDipole2

All Implemented Interfaces:

IElectromagnet, IComponent, IElement

public class IdealMagSectorDipole2
extends ThickElectromagnet

Represents a bending magnetic dipole magnet for a beam in a sector configuration. Thus, there are no edge effects as the beam enters the magnet orthogonally.

The MAD convention for sector magnets is followed for coordinates, signs, and lengths. The formulation from D. Carey's Optics book, Transport manual, and H. Wiedemann's books are used.

NOTES:

Both the dipole effects and the quadrupole (focusing) effects vary off the design values with differing magnetic field strengths. This situation is in contrast with the previous version of this class where only the quadrupole effects varied, and in contract with the class ThickDipole where only the dipole effects varied.

References

[1] D.C. Carey, The Optics of Charged Particle Beams (Harwood, 1987)
[2] H. Wiedemann, Particle Accelerator Physics I, 2nd Ed. (Springer, 1999)

See Also:

IdealMagSectorDipole2, ThickDipole

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	s_strEntranceAngle Tag for parameters in the XML configuration file
static java.lang.String	s_strExitAngle Tag for parameters in the XML configuration file
static java.lang.String	s_strField Tag for parameters in the XML configuration file
static java.lang.String	s_strPathLength Tag for parameters in the XML configuration file
static java.lang.String	s_strQuadComponent Tag for parameters in the XML configuration file
static java.lang.String	s_strType string type identifier for all IdealMagSectorDipole objects

Fields inherited from class xal.model.elem.ThickElectromagnet

dblField, enmOrient

Fields inherited from interface xal.model.elem.IElectromagnet

ORIENT_HOR, ORIENT_NONE, ORIENT_VER

Fields inherited from interface xal.model.IElement

LightSpeed, Permeability, Permittivity, UnitCharge

Constructor Summary

Constructors

Constructor and Description
IdealMagSectorDipole2() Default constructor - creates a new uninitialized instance of IdealMagSectorDipole.
IdealMagSectorDipole2(java.lang.String strId) Default constructor - creates a new uninitialized instance of IdealMagSectorDipole.
IdealMagSectorDipole2(java.lang.String strId, double dblLen, int enmOrient, double dblFld, double dblGap, double dblFldInd) Creates a new instance of IdealMagSectorDipole

Method Summary

Modifier and Type	Method and Description
double	compDesignBendingRadius() Compute and return the bending radius of the design orbit throught the magnet.
double	compDesignCurvature() Compute and return the curvature of the design orbit through the magnet.
double	compPathLengthVariationFactor(IProbe probe) Computes and returns the path length variation factor.
double	compProbeCurvature(IProbe probe) Compute the path curvature within the dipole for the given probe.
double	compQuadrupoleConstant(IProbe probe) Compute and return the quadrupole focusing constant for the current dipole settings and the given probe.
double	elapsedTime(IProbe probe, double dblLen) Returns the time taken for the probe to drift through part of the element.
double	energyGain(IProbe probe, double dblLen) Return the energy gain imparted to a particular probe.
double	getDesignBendingAngle() Return the bending angle of the magnet's design trajectory.
double	getDesignPathLength() Return the path length of the design trajectory through the magnet.
double	getFieldIndex() Return the magnetic field index of the magnet evaluated at the design orbit.
boolean	getFieldPathFlag() Return the field path flag.
double	getGapHeight() Return the gap size between the dipole magnet poles.
double	getK0() This is the design bending curvature h = 1/R0 where R0 is the design bending radius.
double	getQuadComponent() Returns the quadrupole field component of the bending magnet.
void	print(java.io.PrintWriter os) Dump current state and content to output stream.
void	setDesignBendAngle(double dblBendAng) Set the bending angle of the reference (design) orbit.
void	setDesignPathLength(double dblPathLen) Set the reference (design) orbit path-length through the magnet.
void	setFieldIndex(double dblFldInd) Set the magnetic field index of the magnet evaluated at the design orbit.
void	setFieldPathFlag(boolean ba) sako - to set field path flag.
void	setGapHeight(double dblGap) Set the gap size between the dipole magnet poles.
void	setK0(double dbl) Set the design curvature h of the bending magnet.
void	setQuadComponent(double dbl) quad K1 component defined in SAD (=normal k1 * L)
PhaseMap	transferMap(IProbe probe, double dblLen) Compute the partial transfer map of an ideal sector magnet for the particular probe.

Methods inherited from class xal.model.elem.ThickElectromagnet

getMagField, getOrientation, initializeFrom, setMagField, setOrientation

Methods inherited from class xal.model.elem.ThickElement

getLength, setLength

Methods inherited from class xal.model.elem.Element

addCloseElements, applyAlignError, backPropagate, backPropagate, compDriftingTime, compProbeLocation, getAlignX, getAlignY, getAlignZ, getCloseElements, getHardwareNodeId, getId, getPosition, getType, getUID, propagate, propagate, setAlign, setAlignX, setAlignY, setAlignZ, setHardwareNodeId, setId, setPosition, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

s_strType

public static final java.lang.String s_strType

string type identifier for all IdealMagSectorDipole objects

See Also:

Constant Field Values

s_strPathLength

public static final java.lang.String s_strPathLength

Tag for parameters in the XML configuration file

See Also:

Constant Field Values

s_strField

public static final java.lang.String s_strField

Tag for parameters in the XML configuration file

See Also:

Constant Field Values

s_strEntranceAngle

public static final java.lang.String s_strEntranceAngle

Tag for parameters in the XML configuration file

See Also:

Constant Field Values

s_strExitAngle

public static final java.lang.String s_strExitAngle

Tag for parameters in the XML configuration file

See Also:

Constant Field Values

s_strQuadComponent

public static final java.lang.String s_strQuadComponent

Tag for parameters in the XML configuration file

See Also:

Constant Field Values

Constructor Detail

IdealMagSectorDipole2

public IdealMagSectorDipole2()

Default constructor - creates a new uninitialized instance of IdealMagSectorDipole. This is the constructor called in automatic lattice generation. Thus, all element properties are set following construction.

IdealMagSectorDipole2

public IdealMagSectorDipole2(java.lang.String strId)

Default constructor - creates a new uninitialized instance of IdealMagSectorDipole. This is the constructor called in automatic lattice generation. Thus, all element properties are set following construction.

IdealMagSectorDipole2

public IdealMagSectorDipole2(java.lang.String strId,
                             double dblLen,
                             int enmOrient,
                             double dblFld,
                             double dblGap,
                             double dblFldInd)

Creates a new instance of IdealMagSectorDipole

Parameters:

strId - identifier for this IdealMagSectorDipole object

dblFld - field gradient strength (in Tesla)

dblLen - pathLength of the dipole (in m)

dblGap - full pole gap of the dipole (in m)

dblFldInd - The dimensionless integral term for the extended fringe field focusing, Should be = 1/6 for linear drop off, ~ 0.4 for clamped Rogowski coil, or 0.7 for an unclamped Rogowski coil. (dimensionless)

Method Detail

getK0

public double getK0()

This is the design bending curvature h = 1/R₀ where R₀ is the design bending radius.

Returns:

the design curvature of the bending magnet

Since:

Apr 19, 2011

setK0

public void setK0(double dbl)

Set the design curvature h of the bending magnet.

Parameters:

dbl - design curvature h = 1/R₀ where R₀ is the design path radius.

Since:

Apr 19, 2011

setFieldIndex

public void setFieldIndex(double dblFldInd)

Set the magnetic field index of the magnet evaluated at the design orbit. The field index is defined as n := -(R0/B0)(dB/dR) where R0 is the radius of the design orbit, B0 is the field at the design orbit (@see IdealMagSectorDipole#getField), and dB/dR is the derivative of the field with respect to the path deflection - evaluated at the design radius R0.

Parameters:

dblFldInd - field index of the magnet (unitless)

setQuadComponent

public void setQuadComponent(double dbl)

quad K1 component defined in SAD (=normal k1 * L)

setGapHeight

public void setGapHeight(double dblGap)

Set the gap size between the dipole magnet poles.

Parameters:

dblGap - gap size in meters

setDesignPathLength

public void setDesignPathLength(double dblPathLen)

Set the reference (design) orbit path-length through the magnet.

Parameters:

dblPathLen - path length of design trajectory (meters)

setDesignBendAngle

public void setDesignBendAngle(double dblBendAng)

Set the bending angle of the reference (design) orbit.

Parameters:

dblBendAng - design trajectory bending angle (radians)

setFieldPathFlag

public void setFieldPathFlag(boolean ba)

sako - to set field path flag. true means use design path throughout.

Parameters:

ba - new field path flag value

getFieldIndex

public double getFieldIndex()

Return the magnetic field index of the magnet evaluated at the design orbit. The field index is defined as

n := -(R0/B0)(dB/dR)

where R0 is the radius of the design orbit, B0 is the field at the design orbit (see IdealMagSectorDipole#getField), and dB/dR is the derivative of the field with respect to the path deflection - evaluated at the design radius R0.

Returns:

field index of the magnet at the design orbit (unitless)

getQuadComponent

public double getQuadComponent()

Returns the quadrupole field component of the bending magnet.

Returns:

quadrupole field component of this magnet

getGapHeight

public double getGapHeight()

Return the gap size between the dipole magnet poles.

Returns:

gap size in meters

getDesignPathLength

public double getDesignPathLength()

Return the path length of the design trajectory through the magnet.

Returns:

design trajectory path length (in meters)

getDesignBendingAngle

public double getDesignBendingAngle()

Return the bending angle of the magnet's design trajectory.

Returns:

design trajectory bending angle (in radians)

getFieldPathFlag

public boolean getFieldPathFlag()

Return the field path flag.

Returns:

field path flag = 1 (use design field) or 0 (use bField parameter)

compDesignCurvature

public double compDesignCurvature()

Compute and return the curvature of the design orbit through the magnet. Note that this value is the inverse of the design curvature radius R0.

Returns:

the design curvature 1/R0 (in 1/meters)

See Also:

compDesignBendingRadius()

compDesignBendingRadius

public double compDesignBendingRadius()

Compute and return the bending radius of the design orbit throught the magnet. Note that this value is the inverse of design curvature h0.

Returns:

the design bending radius R0 (in meters)

See Also:

compDesignCurvature()

compProbeCurvature

public double compProbeCurvature(IProbe probe)

Compute the path curvature within the dipole for the given probe. The path curvature is 1/R where R is the bending radius of the dipole (radius of curvature). Note that for zero fields the radius of curvature is infinite while the path curvature is zero.

Parameters:

probe - probe object to be deflected

Returns:

dipole path curvature for given probe (in 1/meters)

compQuadrupoleConstant

public double compQuadrupoleConstant(IProbe probe)

Compute and return the quadrupole focusing constant for the current dipole settings and the given probe. The curvature for the current magnet settings and probe state is used - making this a dynamic quantity. The field index does not change within the magnet.

NOTE:

- This value may be negative if the resulting curvature is negative This condition means we are bending toward the negative x direction and does not imply defocusing.

- This value is essentially the same as the field index of the magnet - the two values differ by a constant, the curvature squared. The square-root of this value provides the betatron phase advance wave number.

K_quad := (1/R)(1/B)(dB/dR) = - h^2 * n0

where K_quad is the quadrupole focusing constant, R is the bending radius at current settings, B is the current magnet field strength , h = 1/R is the curvature at the current settings, and n0 is the field index.

Parameters:

probe - we use the probe velocity to determine curvature

Returns:

quadrupole focusing constant (in 1/meters^2)

compPathLengthVariationFactor

public double compPathLengthVariationFactor(IProbe probe)

Computes and returns the path length variation factor. This is the factor by with the synchronous particle path length expands or contracts about the design path length when considering the effects of dipole field strength other than the design value. Denoting this quantity as w then it can be expressed

w = 1 - h/h₀ ,

where h₀ is the bending curvature of the design field and h is the bending curvature of the current field strength. Thus, for a distance Δs₀ along the design path, the synchronous particle actually travels a distance

Δs = wΔs₀

along the actual path.

Parameters:

probe - probe moving a some velocity determining the bending curvature

Returns:

the path length variation factor w

Since:

Nov 27, 2013

elapsedTime

public double elapsedTime(IProbe probe,
                          double dblLen)

Returns the time taken for the probe to drift through part of the element.

Specified by:

elapsedTime in interface IElement

Specified by:

elapsedTime in class Element

Parameters:

probe - propagating probe

dblLen - length of subsection to propagate through meters

Returns:

the elapsed time through sectionUnits: seconds

energyGain

public double energyGain(IProbe probe,
                         double dblLen)

Return the energy gain imparted to a particular probe. For an ideal quadrupole magnet this value is always zero.

Specified by:

energyGain in interface IElement

Specified by:

energyGain in class ThickElement

Parameters:

dblLen - dummy argument

probe - dummy argument

Returns:

returns a zero value

transferMap

public PhaseMap transferMap(IProbe probe,
                            double dblLen)
                     throws ModelException

Compute the partial transfer map of an ideal sector magnet for the particular probe. Computes transfer map for a section of magnet h meters in length.

NOTE

The arc length dL of the probe will probably be larger than the physical step length h. This is because the path length of the design trajectory is generally larger than the physical length (otherwise no bending would occur).

Specified by:

transferMap in interface IElement

Specified by:

transferMap in class ThickElement

Parameters:

dblLen - physical step length (meters)

probe - uses the rest and kinetic energy parameters from the probe

Returns:

transfer map of ideal sector magnet for particular probe

Throws:

ModelException - unknown quadrupole orientation

See Also:

IElement.transferMap(IProbe,double)

print

public void print(java.io.PrintWriter os)

Dump current state and content to output stream.

Overrides:

print in class Element

Parameters:

os - output stream object