Robert Molo

(1)

An Introduction to ELEctron Generation ANd Tracking ELEGANT

(2)

Advantages of ELEGANT

Support by Michael Borland (forum)

ELEGANT is continuously being developed further

SDDS Toolkit → read data produced by other programs

Used by groups at SLAC, DESY, SOLEIL, DELTA ...

Uses a variant of the MAD input format ...

(3)

Simulation Capabilities

Tracking of rings, linacs, and transport lines (6D)

Computation of s-dependent and final properties (e.g. Twiss parameters)

Optimization of results of computations and tracking

...

(4)

Setting up a Simulation

Setup and action commands Lattice description

run.ele lat.lte

(5)

Macros

<tag1> will be replaced by value1 before simulation

→ bash scripts, python, matlab, ….

example: change the strength of one quadrupole

(6)

run.ele: General Command Syntax

&<namelist-name>

<variable-name> = <variable-value>;

. . .

&end

Exmaple:

&run_setup

lattice = "lat.lte",

use_beamline = "DBA", p_central_mev= 1500, default_order = 1,

&end

(7)

lat.lte: General Command Syntax

ElementName: <Element>, <property1>=value1, …

BeamlineName: LINE=(ElementName1,ElementName2,...)

Exmaple:

D1: DRIFT,L=2.340700 D2: DRIFT,L=0.25

DBA: LINE=(B,D1,Q1,D2,Q2,D2,Q1,D1,B)

(8)

Triplet Achromat: lat.lte

! Drifts

D1: DRIFT,L=2.340700 D2: DRIFT,L=0.25

! Quads

Q1: KQUAD,L=0.25,K1=0.5 Q2: KQUAD,L=0.25,K1=-1.0

! Bending Magnet

B: RBEN,L=0.25,ANGLE="3.0 180.0 / pi *"

! Marker

S: MARK, fitpoint=1

! Beamline

DBA: LINE=(S,B,D1,Q1,D2,Q2,D2,Q1,D1,B) RETURN

(9)

Triplet Achromat: run.ele

! Run Setup with Elements

&run_setup

use_beamline = "DBA", p_central_mev= 1500, default_order = 1,

&end

! Calcualte Twiss Parameter for Beamline

&twiss_output

filename = "%s.twi", matched=1,

statistics = 1,

&end

(10)

Triplet Achromat: Simulation

elegant run.ele → start simulation sddsquery run.twi →

17 columns of data:

NAME UNITS SYMBOL FORMAT TYPE FIELD DESCRIPTION s m NULL NULL double 0 Distance

betax m $gb$r$bx$n NULL double 0 Horizontal beta-function alphax NULL $ga$r$bx$n NULL double 0 Horizontal alpha-function psix rad $gy$r$bx$n NULL double 0 Horizontal phase advance etax m $gc$r$bx$n NULL double 0 Horizontal dispersion

etaxp NULL $gc$r$bx$n$a'$n NULL double 0 Slope of horizontal dispersion xAperture m a$bx,eff$n NULL double 0 Effective horizontal aperture betay m $gb$r$by$n NULL double 0 Vertical beta-function

alphay NULL $ga$r$by$n NULL double 0 Vertical alpha-function psiy rad $gy$r$by$n NULL double 0 Vertical phase advance etay m $gc$r$by$n NULL double 0 Vertical dispersion

etayp NULL $gc$r$by$n$a'$n NULL double 0 Slope of vertical dispersion ...

(11)

Triplet Achromat: Simulation

sddsplot run.twi -col=s,betax →

(12)

Triplet Achromat: Simulation

sddsplot run.twi -col=s,etax →

(13)

Triplet Achromat: run.ele optimization

&run_control n_steps = 1 &end

! set up lattice optimization

&optimization_setup

mode = minimize, method = simplex, n_passes = 100,

n_evaluations = 100, n_restarts = 100,

&end

! optimization term

&optimization_term term = "S#1.etax abs" &end

(14)

Triplet Achromat: run.ele optimization

! optimization parameters

&optimization_variable name=Q1, item=K1, lower_limit=-5, upper_limit=5, step_size=10.0 &end

&optimization_variable name=Q2, item=K1, lower_limit=-5, upper_limit=5, step_size=10.0 &end

&optimization_variable name=D1, item=L, lower_limit=0.00, upper_limit=3.0, step_size=0.05 &end

&optimization_variable name=D2, item=L, lower_limit=0.00, upper_limit=1.0, step_size=0.05 &end

(15)

Triplet Achromat: run.ele optimization

! start optimization

&bunched_beam n_particles_per_bunch=1 &end

&optimize summarize_setup=1 &end

&save_lattice filename = %s_optimized.lte &end

(16)

Triplet Achromat: run.ele optimization

&run_control n_steps = 1 &end

! set up lattice optimization

&optimization_setup

mode = minimize, method = simplex, n_passes = 100,

n_evaluations = 100, n_restarts = 100,

&end

! optimization term

&optimization_term term = "S#1.etax abs" &end

(17)

Triplet Achromat: run.ele optimization

Optimization results:

optimization function has value 0.00654441482207175 Terms of equation:

S#1.etax abs: 6.544414822071749e-03

A total of 10698 function evaluations were made.

Optimum values of variables and changes from initial values:

Q1.K1: 2.334229754519380e+00 1.8342297545193e+00 Q2.K1: -3.125142643677447e+00 -2.1251426436774e+00 D1.L: 2.946343708813805e+00 6.0564370881380e-01 D2.L: 9.961497476644054e-01 7.4614974766440e-01 End of input data encountered.

(18)

Triplet Achromat: run.ele optimization

sddsplot run_optimzed.twi -col=s,etax →

(19)

Particle Tracking: run.ele

&run_setup

use_beamline = "TEST", p_central_mev= 1500, default_order = 1,

&end

&run_control

n_steps = 1

&end

(20)

Particle Tracking: run.ele

&bunched_beam

n_particles_per_bunch =10000, one_random_bunch=0,

sigma_dp = 6.8e-4, sigma_s = 3e-4, emit_x=15e-9, emit_y=1.5e-9, beta_x=10,

beta_y=10, alpha_x=0,

alpha_y=0, eta_x=0, eta_y=0, etap_x=0, etap_y=0,

distribution_type[0] = "gaussian","gaussian","gaussian", distribution_cutoff[0] = 5,5,5,

&end

(21)

Particle Tracking: lat.lte

! Drifts

D1: DRIFT,L=2.340700

! Watch

W1: WATCH,FILENAME="%s-%03ld.w1"

! Laser-electron interaction

UA:LSRMDLTR,l=2.25,periods=9,Bu=0.44,accuracy=1e-3,&

method="non-adaptive",n_steps=100,&

LASER_PEAK_POWER=15.5e10,LASER_Z0=0.0,&

LASER_W0=15.65685424949238e-04,&

field_expansion="ideal",&

LASER_WAVELENGTH=800e-9,&

time_offset=0,&

time_profile="laserProfile.sdds=t+A"&

! Beamline

TEST: LINE=(W1,UA,D1,W1)

(22)

Particle Tracking: lat.lte

sddsplot run-001.w1 -col=t,p -graph=dots

(23)

Particle Tracking: lat.lte

sddsplot run-002.w1 -col=t,p -graph=dots

(24)

Reference

http://www.aps.anl.gov/Accelerator_Systems_Divisio n/Accelerator_Operations_Physics/software.shtml