AT cheatsheet

Available element types

• Aperture

ataparture(FAMNAME,[-x,+x,-y,+y],'AperturePass');

define physical aperture element (collimator)

• Base element

atbaselem

• Drift:

atdrift(FAMNAME,LENGTH,'DriftPass')

• Sector Bend/Rectangular Bend:

atrbend/atsbend(FAMNAME,LENGTH,BENDINGANGLE,PASSMETHOD)

PASSMETHODs: 'BndMPoleSymplectic4Pass', 'BndMPoleSymplectic4RadPass', 'BndMPoleSymplectic4E2Pass', 'BndMPoleSymplectic4E2RadPass', 'BndMPoleSymplectic4FrgGPass', 'BndMPoleSymplectic4FrgFradPass', 'BendLinearPass'

• Quadrupole:

atquadrupole(FAMNAME,LENGTH,K,PASSMETHOD)

PASSMETHODs: 'StrMPoleSymplectic4Pass', 'StrMPoleSymplectic4RadPass, QuadLinearPass, QuadMPoleFringePass, QuadMPoleFringeRadPass, ThinMPolePass'

• Sextupole:

atsextupole(FAMNAME,LENGTH,S,PASSMETHOD)

PASSMETHODs: 'StrMPoleSymplectic4Pass', 'StrMPoleSymplectic4RadPass', 'ThinMPolePass'

• Octupole:

octupole(FAMNAME,LENGTH, S, PASSMETHOD)

PASSMETHODs: 'StrMPoleSymplectic4Pass,StrMPoleSymplectic4RadPass'

• Multipole

ATMULTIPOLE(FAMNAME,LENGTH,POLYNOMA,POLYNOMB,PASSMETHOD)

PASSMETHODs: 'StrMPoleSymplectic4Pass,StrMPoleSymplectic4RadPass','ThinMPolePass'

• ThinMultipole

atthinmultipole(FAMNAME,PolynomA,PolynomB,'ThinMPolePass')

• Wiggler

atwiggler(FAMNAME, Ltot,Lw,Bmax,Nstep,Nmeth,By,Bx,PASSMETHOD)

PASSMETHODS: 'GWigSymplecticPass', 'WigLinearPass'

• KickMap (Insertion Device)

atidtable(Nslice,filename,Energy,'IDTablePass')

• RFCavity

atrfcavity(FAMNAME,LENGTH,VOLTAGE,FREQUENCY,HARMNUMBER,ENERGY,'CavityPass')

• QuantDiff

atQuantDiff(FAMNAME,?,'QuantDiffPass')

• Monitor

atmonitor(FAMNAME,'FIELDNAME1',VALUE1,...,'IdentityPass')

• Marker

atmarker(FAMNAME,'FIELDNAME1',VALUE1,...,'IdentityPass');

• Corrector

atcorrector(FAMNAME,LENGTH,KICK,PASSMETHOD);

• Solenoid

atsolenoid(FAMNAME,LENGTH, KS,'SolenoidLinearPass');

• Matrix66

atM66(FAMNAME,?,'Matrix66Pass')

• RingParam

ATRINGPARAM(FAMNAME,E0,NBPERIODS);

NOTE: all elements may be misaligned (T1,2) or rotated (R1,2)

Pass methods

passfunction: Pass method written in C

mexfunction: interface to MatLab is via the Mex function for each passmethod

Lattice: creation and manipulation

Cell = [{Elem1}; {Elem2}; ...; {NthElem}];

Ring = repmat(Cell,Ntimes,1);

To find and modify elements:

• findcells: allows to find indices of elements in the lattice using various criteria
  • eg. QFindices = findcells(FODO,'FamName','QF');
  • eg. QFIndices = findcells(FODO,'Class','Quadrupole')
• getcellstruct: to extract the fields with the elements
  • eg. to retrieve quadrupole strength values Kvals = getcellstruct(FODO,'PolynomB',QuadIndices,2);
• setcellstruct: may be used to set the values of parameters
  • eg. add some random errors to all the quadrupole strengths with

  Kvals = Kvals + 0.2*(rand(length(Kvals),1)-0.5); 
  FODOerr = setcellstruct(FODO,'PolynomB',QuadIndices,Kvalserr,2);
  

• findspos: to find the longitudinal position of each element of a certain family/class
  • eg. quadpos = findspos(FODO,QuadIndices);

Tracking

• ringpass: this is the function that does the tracking
• eg. nturns=200; Z01=[.001;0;0;0;0;0]*(1:3); Z200=ringpass(FODO,Z01,nturns);

NOTE: it can be convenient to cast ZZ200=reshape(Z200,6,3,nturns); ZZZn = ZZ200(:,n,:); when tracking multiple particles

Computation of beam parameters

• [param,tune,chrom]= atlinopt(FODO,offenergy,observationpointelementnumber)

where

param = struct array with following fields:

• ElemIndex
• SPos
• ClosedOrbit
• Dispersion
• M44
• gamma
• C
• A
• B
• beta
• alpha
• mu

eg. to access beta function beta=param.beta;betax=beta(:,1);

• atplot([FODO;FODO]);

Beam sizes

• atx: To take into account radiation and compute both linear optics and beam sizes
• eg. [beamdata,params]=atx(FODOwCav);

NOTE: it requires the beam to be longitudinally stable

References:

[1] Accelerator Toolbox Collaboration documentation