Package xal.extension.jels.model.elem

Class ThinRfFieldMap

java.lang.Object

xal.model.elem.Element

xal.model.elem.ThinElement

xal.extension.jels.model.elem.ThinRfFieldMap

All Implemented Interfaces:

IRfCavityCell, IRfGap, IComponent, IElement

public class ThinRfFieldMap
extends ThinElement
implements IRfGap, IRfCavityCell

Thin element version for RF field map implementation. This class allows superposition to other fieldmaps, but has the overhead of creating an element for every point in the fieldmap.

You should use ThickRfFieldMap for big non-superposed fieldmaps for high performance.

Author:

Juan F. Esteban Müller <JuanF.EstebanMuller@esss.se>

Field Summary

Fields inherited from class xal.model.elem.Element

dblNodeLen, dblNodePos

Fields inherited from interface xal.model.IElement

LIGHT_SPEED, PERMEABILITY, PERMITTIVITY, UNIT_CHARGE

Constructor Summary

Constructors

Constructor	Description
ThinRfFieldMap()
ThinRfFieldMap(String strId)

Method Summary

Modifier and Type	Method	Description
void	computeSynchronousPhaseAndEnergyGain(IProbe probe)	Compute the synchronous phase and the energy gain for a cavity gap.
protected double	elapsedTime(IProbe probe)	Returns the time taken for the probe to propagate through element.
protected double	energyGain(IProbe probe)	Calculate the energy gain for this element on the supplied probe.
int	getCavityCellIndex()	Returns the index of this cell within the parent RF cavity.
double	getCavityModeConstant()	Returns the structure mode number q for the cavity in which this gap belongs.
double	getCellLength()
double	getDeltaPhi()
double	getE0()	Get the on accelerating field (V/m)
double	getEnergyGain()	Return the energy gain of a cavity gap previously calculated.
double	getETL()	Return the ETL product of the gap, where E is the longitudinal electric field, T is the transit time factor, and L is the gap length.
double	getFrequency()	Get the operating frequency of the RF gap.
double	getLongitudinalPhaseReference()
double	getPhase()	Return the RF phase delay of the gap with respect to the synchronous particle.
double	getSynchronousPhase()	Return the synchronous phase of a cavity gap, which must be previously calculated using computeSynchronousPhase.
void	initializeFrom(LatticeElement element)	Conversion method to be provided by the user
boolean	isEndCell()	Returns whether or not the cell is the first or last in a string of cells within an RF cavity.
boolean	isFirstCell()	Indicates whether or not this cell is the first cell of an RF cavity.
protected double	longitudinalPhaseAdvance(IProbe probe)	Again, this is a kluge.
void	setCavityCellIndex(int indCell)	Set the index n of this cell within the enclosing RF cavity.
void	setCavityModeConstant(double dblCavModeConst)	Sets the structure mode number q for the cavity in which this cell belongs.
void	setCellLength(double cellLength)
void	setDeltaPhi(double deltaPhi)
void	setE0(double cavAmp)	Set the on accelerating field.
void	setETL(double dblETL)	Set the ETL product of the RF gap where E is the longitudinal electric field of the gap, T is the transit time factor of the gap, L is the length of the gap.
void	setFrequency(double dblFreq)	Set the operating frequency of the RF gap.
void	setLongitudinalPhaseReference(double longitudinalPhaseEntrance)
void	setPhase(double cavPhase)	Set the phase delay of the RF in gap with respect to the synchronous particle.
PhaseMap	transferMap(IProbe probe)	Method calculates transfer matrix for the field map for a given data point in the field map.Drift spaces are calculated separately.

Methods inherited from class xal.model.elem.ThinElement

applyErrors, elapsedTime, energyGain, getLength, longitudinalPhaseAdvance, transferMap

Methods inherited from class xal.model.elem.Element

addCloseElements, backPropagate, backPropagate, compDriftingTime, compProbeLocation, getAlignX, getAlignY, getAlignZ, getCloseElements, getHardwareNodeId, getId, getLatticePosition, getNodeLen, getNodePos, getParent, getPhiX, getPhiY, getPhiZ, getPosition, getType, getUID, print, propagate, propagate, setAlign, setAlignX, setAlignY, setAlignZ, setHardwareNodeId, setId, setParent, setPhiX, setPhiY, setPhiZ, setPosition, toString

Methods inherited from class java.lang.Object

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

Constructor Details

ThinRfFieldMap

public ThinRfFieldMap()

ThinRfFieldMap

public ThinRfFieldMap(String strId)

Method Details

getCellLength

public double getCellLength()

setCellLength

public void setCellLength(double cellLength)

getDeltaPhi

public double getDeltaPhi()

setDeltaPhi

public void setDeltaPhi(double deltaPhi)

initializeFrom

public void initializeFrom(LatticeElement element)

Description copied from class: Element

Conversion method to be provided by the user

Specified by:

initializeFrom in interface IComponent

Overrides:

initializeFrom in class Element

Parameters:

element - the SMF node to convert

transferMap

public PhaseMap transferMap(IProbe probe)
                     throws ModelException

Method calculates transfer matrix for the field map for a given data point in the field map.Drift spaces are calculated separately.

Specified by:

transferMap in class ThinElement

Parameters:

probe -

Returns:

Throws:

ModelException

longitudinalPhaseAdvance

protected double longitudinalPhaseAdvance(IProbe probe)

Description copied from class: ThinElement

Again, this is a kluge. We return zero since the notion of frequency is not defined for every element (perhaps if this element is the child of an RF cavity). For those elements that do create a phase advance they need to override this method.

There is some legitimacy in returning zero since a thin element generally has no phase advance. That is, there is no propagation therefore no elapsed time and no phase advance. Only if there is energy gain must there be a corresponding conjugate phase advance.

Overrides:

longitudinalPhaseAdvance in class ThinElement

Parameters:

probe - probe experiencing a phase advance through this element

Returns:

the change in phase while going through the element

elapsedTime

protected double elapsedTime(IProbe probe)

Description copied from class: ThinElement

Returns the time taken for the probe to propagate through element.

Specified by:

elapsedTime in class ThinElement

Parameters:

probe - propagating probe

Returns:

elapsed time through element Units: seconds

energyGain

protected double energyGain(IProbe probe)

Calculate the energy gain for this element on the supplied probe.

This implementation assumes that this method is always called after the transferMap method. This is true for the EnvelopeTracker, but might differ for other algorithms.

Specified by:

energyGain in class ThinElement

Returns:

this element's energy gain

setETL

public void setETL(double dblETL)

Description copied from interface: IRfGap

Set the ETL product of the RF gap where E is the longitudinal electric field of the gap, T is the transit time factor of the gap, L is the length of the gap. The maximum energy gain from the gap is given by qETL where q is the charge (in Coulombs) of the species particle.

Specified by:

setETL in interface IRfGap

Parameters:

dblETL - ETL product of gap (in volts).

setE0

public void setE0(double cavAmp)

Description copied from interface: IRfGap

Set the on accelerating field. This method should be called by the RF cavity containing this gap and should use the amplitude factor.

Specified by:

setE0 in interface IRfGap

Parameters:

cavAmp - - the on axis field (V/m)

setPhase

public void setPhase(double cavPhase)

Description copied from interface: IRfGap

Set the phase delay of the RF in gap with respect to the synchronous particle. The actual energy gain from the gap is given by qETLcos(dblPhi) where dbkPhi is the phase delay. This method should be called by the RF cavity containing this gap and should use the phase factor.

Specified by:

setPhase in interface IRfGap

Parameters:

cavPhase - phase delay of the RF w.r.t. synchronous particle (in radians).

setFrequency

public void setFrequency(double dblFreq)

Description copied from interface: IRfGap

Set the operating frequency of the RF gap.

Specified by:

setFrequency in interface IRfGap

Parameters:

dblFreq - frequency of RF gap (in Hertz)

getETL

public double getETL()

Description copied from interface: IRfGap

Return the ETL product of the gap, where E is the longitudinal electric field, T is the transit time factor, and L is the gap length.

Specified by:

getETL in interface IRfGap

Returns:

the ETL product of the gap (in volts).

getPhase

public double getPhase()

Description copied from interface: IRfGap

Return the RF phase delay of the gap with respect to the synchronous particle.

Specified by:

getPhase in interface IRfGap

Returns:

phase delay w.r.t. synchronous particle (in radians).

getFrequency

public double getFrequency()

Description copied from interface: IRfGap

Get the operating frequency of the RF gap.

Specified by:

getFrequency in interface IRfGap

Returns:

frequency of RF gap (in Hertz)

getE0

public double getE0()

Description copied from interface: IRfGap

Get the on accelerating field (V/m)

Specified by:

getE0 in interface IRfGap

setCavityCellIndex

public void setCavityCellIndex(int indCell)

Description copied from interface: IRfCavityCell

Set the index n of this cell within the enclosing RF cavity. The index origin begins at 0, specifically, the first cell in the cavity will have a cell index of O. Since cell phase φ seen by the probe is

φ = nqπ + φ₀

where q is the cavity structure constant and φ₀ is the klystron driving phase, the first cell always has the phase of the klystron.

When considered with an RF gap, it can be convenient to consider the phase rather as a spatial component of the field and combine it with the field amplitude. We simply get a signum function effect where the new field E>_n at cell n is given by

E_n = E₀ cos(nqπ)

where E₀ is the usual gap field strength.

See the discussion below on cavity mode constants.

Specified by:

setCavityCellIndex in interface IRfCavityCell

Parameters:

indCell - index of the cavity cell within the cavity, starting at 0

setCavityModeConstant

public void setCavityModeConstant(double dblCavModeConst)

Description copied from interface: IRfCavityCell

Sets the structure mode number q for the cavity in which this cell belongs. Here the structure mode number is defined in terms of the fractional phase advance between cells, with respect to π. To make this explicit

q = 0 ⇛ 0 mode
q = 1/2 ⇒ π/2 mode
q = 1 ⇛ π mode

Thus, a cavity mode constant of q = 1/2 indicates a π/2 phase advance between adjacent cells and a corresponding cell amplitude function A_n of

A_n = cos(nqπ)

where n is the index of the cell within the coupled cavity.

Specified by:

setCavityModeConstant in interface IRfCavityCell

Parameters:

dblCavModeConst - the cavity mode structure constant for the cavity containing this cell

See Also:

• RF Linear Accelerators, Thomas P. Wangler (Wiley, 2008).

getCavityCellIndex

public int getCavityCellIndex()

Description copied from interface: IRfCavityCell

Returns the index of this cell within the parent RF cavity. The index origin starts at zero.

Specified by:

getCavityCellIndex in interface IRfCavityCell

Returns:

the cell number within the parent cavity, starting at zero

See Also:

• IRfCavityCell.setCavityCellIndex(int)

getCavityModeConstant

public double getCavityModeConstant()

Description copied from interface: IRfCavityCell

Returns the structure mode number q for the cavity in which this gap belongs. This is the fractional phase advance between cells, with respect to π. It can also be interpreted as describing the spatial advance of the axial electric field from cell to cell.

Specified by:

getCavityModeConstant in interface IRfCavityCell

Returns:

the cavity mode constant for the cell containing this gap

See Also:

• RF Linear Accelerators, Thomas P. Wangler (Wiley, 2008).
• IRfCavityCell.setCavityModeConstant(double)

isEndCell

public boolean isEndCell()

Description copied from interface: IRfCavityCell

Returns whether or not the cell is the first or last in a string of cells within an RF cavity. This is particularly important in structures operating outside 0 mode where the cell phasing may change.

Specified by:

isEndCell in interface IRfCavityCell

Returns:

true if this cell is at either end in a bank of cells, false otherwise

isFirstCell

public boolean isFirstCell()

Description copied from interface: IRfCavityCell

Indicates whether or not this cell is the first cell of an RF cavity.

Specified by:

isFirstCell in interface IRfCavityCell

Returns:

true if this is the initial cell in an RF cavity, false otherwise

computeSynchronousPhaseAndEnergyGain

public void computeSynchronousPhaseAndEnergyGain(IProbe probe)

Description copied from interface: IRfGap

Compute the synchronous phase and the energy gain for a cavity gap.

Specified by:

computeSynchronousPhaseAndEnergyGain in interface IRfGap

getSynchronousPhase

public double getSynchronousPhase()

Description copied from interface: IRfGap

Return the synchronous phase of a cavity gap, which must be previously calculated using computeSynchronousPhase.

Specified by:

getSynchronousPhase in interface IRfGap

Returns:

synchronous phase [rad]

getEnergyGain

public double getEnergyGain()

Description copied from interface: IRfGap

Return the energy gain of a cavity gap previously calculated.

Specified by:

getEnergyGain in interface IRfGap

Returns:

setLongitudinalPhaseReference

public void setLongitudinalPhaseReference(double longitudinalPhaseEntrance)

Specified by:

setLongitudinalPhaseReference in interface IRfCavityCell

getLongitudinalPhaseReference

public double getLongitudinalPhaseReference()

Specified by:

getLongitudinalPhaseReference in interface IRfCavityCell