OBLA simulations run by Bo Liu

Simulation software: IMPACT-T, written by Ji Qiang (LBNL), modified by Andreas Adelmann and Christof Kraus (PSI)
Visualization: H5PartROOT
Setup: based on FEL-PM84-005-01 (Marco Pedrozzi)
Input distribution obtained from a MAFIA 2.5D simulation (Kevin Li). Python script to convert MAFIA dump to IMPACT-T input.

Solenoid field adjustement

Note: "new" means calculated with ImpactT-V5.1-PSI-2
CASE 1:
CASE 1
Solenoid Parameters Graph1 Graph2 Min. Emit. (mm·mrad) Min. Rms. (mm) Waists Dist. (m)
SP1=160, SP4=095 emittance envelope 0.560994 0.351478 0.006209
SP1=160, SP4=095(new) emittance envelope 0.580595 0.410251 0.011382
SP1=160, SP4=096 emittance envelope 0.555335 0.318099 0.010348
SP1=160, SP4=096(new) emittance envelope 0.578445 0.375422 0.015522
SP1=158, SP4=095 emittance envelope 0.541435 0.305527 0.016556
SP1=158, SP4=095(new) emittance envelope 0.534946 0.365047 0.012418
SP1=158, SP4=094 emittance envelope 0.532988 0.337613 0.013451
SP1=158, SP4=094(new) emittance envelope 0.509660 0.398185 0.009313
SP1=157, SP4=090 emittance envelope 0.527714 0.456240 0.000000
SP1=157, SP4=090(new) emittance envelope 0.460919 0.516585 -0.011383

CASE 2:
CASE 2
Solenoid Parameters Graph1 Graph2 Min. Emit. (mm·mrad) Min. Rms. (mm) Waists Dist. (m)
SP1=150, SP3=070, SP5=085 emittance envelope 0.573372 0.330343 0.035181
SP1=150, SP3=070, SP5=085(new) emittance envelope 0.538699 0.369270 0.023800
SP1=156, SP3=061, SP5=085 emittance envelope 0.598009 0.319575 0.003105
SP1=156, SP3=061, SP5=085(new) emittance envelope 0.483942 0.360603 0.040357
SP1=156, SP3=064, SP5=085 emittance envelope 0.620206 0.348409 -0.007243
SP1=156, SP3=064, SP5=085(new) emittance envelope 0.491595 0.389448 0.044496
SP1=156, SP3=064, SP5=088 emittance envelope 0.580661 0.260879 0.002069
SP1=156, SP3=064, SP5=088(new) emittance envelope 0.472436 0.294947 0.042426

Stability versus IMPACT-T input parameters

Number of particles

CASE 1: (default solenoids: SP1=160, SP4=095)
CASE 1
dt=0.5ps, mesh=016 combined graph
separated graph
dt=0.5ps, mesh=032 combined graph
separated graph
dt=0.5ps, mesh=064 combined graph
separated graph
dt=1.0ps, mesh=064 combined graph
separated graph
dt=2.0ps, mesh=128 combined graph
separated graph

CASE 1m: (modified solenoids: SP1=157, SP4=090)
CASE 1m
dt=0.5ps, mesh=032 combined graph
separated graph
dt=1.0ps, mesh=064 combined graph
separated graph
dt=2.0ps, mesh=128 combined graph
separated graph

Mesh size

CASE 1: (default solenoids: SP1=160, SP4=095)
CASE 1
dt=2.0ps, np=010000 combined graph
separated graph
dt=2.0ps, np=050000 combined graph
separated graph
dt=2.0ps, np=100000 combined graph
separated graph

CASE 1m: (modified solenoids: SP1=157, SP4=090)
CASE 1m
dt=2.0ps, np=050000 combined graph
separated graph
dt=2.0ps, np=100000 combined graph
separated graph

Time step

CASE 1: (default solenoids: SP1=160, SP4=095)
CASE 1
mesh=016, np=010000 combined graph
separated graph
mesh=016, np=100000 combined graph
separated graph
mesh=032, np=010000 combined graph
separated graph
mesh=032, np=100000 combined graph
separated graph
mesh=064, np=010000 combined graph
separated graph
mesh=064, np=100000 combined graph
separated graph

CASE 1m: (modified solenoids: SP1=157, SP4=090)
CASE 1m
mesh=032, np=100000 combined graph
separated graph
mesh=064, np=010000 combined graph
separated graph

Solenoid position

CASE 1: (default solenoids: SP1=160, SP4=095)
Default ImpactT setting: dt=1.0ps, mesh=032, np=010k
CASE 1
sp1 fixed, sp4 move ImpactT
ImpactT-V5.1-PSI-2
sp4 fixed, sp1 move ImpactT
ImpactT-V5.1-PSI-2
sp1 and sp4 move simultaneously ImpactT
ImpactT-V5.1-PSI-2

Study on z-projected parameters and sliced parameters

slice option: centered at mean Z, including 20% particles, uniform weighted
Note:
Z-projected values are not valid when s < 0.012m because bunch head at first step is around there,
also not valid when s > 0.1m because bunch is out of calculation domain

Number of particles

CASE1 (default solenoids: SP1=160, SP4=095):
dt=2.0ps,mesh=032,maxs=0.1m
Emittance(x,px) s around 0.01m projected
sliced
z-projected
np=010k
np=020k
np=050k
np=100k
Emittance(x,px) s=0.05:0.08 projected
sliced
z-projected
Emittance(x,px) s=0.0:0.1 projected
sliced
z-projected
np=010k
np=020k
np=050k
np=100k
Mean(x) projected
sliced
z-projected
np=010k
np=020k
np=050k
np=100k
Mean(px) projected
sliced
z-projected
np=010k
np=020k
np=050k
np=100k

Mesh size

CASE1 (default solenoids: SP1=160, SP4=095):
dt=4.0ps,np=100000,maxs=0.1m
Emittance(x,px) s=0.05:0.08 projected
sliced
z-projected
mesh=008
mesh=016
mesh=032
mesh=064
Emittance(x,px) s=0.0:0.1 projected
sliced
z-projected
mesh=008
mesh=016
mesh=032
mesh=064
Mean(x) projected
sliced
z-projected
mesh=008
mesh=016
mesh=032
mesh=064
Mean(px) projected
sliced
z-projected
mesh=008
mesh=016
mesh=032
mesh=064
dt=4.0ps,np=010000,maxs=0.1m
Emittance(x,px) s=0.05:0.08 projected
sliced
z-projected
mesh=008
mesh=016
mesh=032
mesh=064
Emittance(x,px) s=0.0:0.1 projected
sliced
z-projected
mesh=008
mesh=016
mesh=032
mesh=064
Mean(x) projected
sliced
z-projected
mesh=008
mesh=016
mesh=032
mesh=064
Mean(px) projected
sliced
z-projected
mesh=008
mesh=016
mesh=032
mesh=064

Time step

CASE1 (default solenoids: SP1=160, SP4=095):
mesh=032,np=010000,maxs=0.1m
Emittance(x,px) s around 0.01m projected
sliced
z-projected
dt=0.5ps
dt=1.0ps
dt=2.0ps
dt=4.0ps
Emittance(x,px) s=0.0:0.1 projected
sliced
z-projected
dt=0.5ps
dt=1.0ps
dt=2.0ps
dt=4.0ps
Mean(x) projected
sliced
z-projected
dt=0.5ps
dt=1.0ps
dt=2.0ps
dt=4.0ps
Mean(px) dt=0.5ps
dt=1.0ps
dt=2.0ps
dt=4.0ps

Comparison with MAFIA

Without Solenoids
Slice Emittance graph
note: slice is centered at Mean pos, length is 1.0 ps and uniform weighted
Slice Emittance graph
note: slice is centered at Mean pos, including 20% particles and uniform weighted
Zproj. Emittance graph
note: value not valid at s < 0.011m
MAFIA result graph
note: provided by Kevin Li

Alignment studies

With default IMPACT-T settings:
Nptcl = 10k,
Nx = Ny = Nz = 32,
dt = 4.0e-12,
CASE 1: (default solenoids: SP1=160, SP4=095)
some typical cases for 50 µm. alignment error
sp1 without error, sp4 error in x emittance
envelope
sp1 without error, sp4 error in x and y emittance
envelope
sp1 error in x, sp4 without error emittance
envelope
sp1 error in x, sp4 error in y emittance
envelope
sp1 error in x, sp4 error in x emittance
envelope
sp1 error in x, sp4 error in x and y emittance
envelope
sp1 error in x, sp4 error in -x emittance
envelope
sp1 error in x and y, sp4 without error emittance
envelope
sp1 error in x and y, sp4 error in x emittance
envelope
sp1 error in x and y, sp4 error in x and y emittance
envelope
sp1 error in x and y, sp4 error in x and -y emittance
envelope
sp1 error in x and y, sp4 error in -x emittance
envelope
sp1 error in x and y, sp4 error in -x and -y emittance
envelope


Random Error
move solenoids in x and y by random off-set
case 1, random offsets, max = 5 µm. x plane
y plane
case 1, random offsets, max = 5 µm. (new) x plane
y plane
case 1, random offsets, max = 10 µm. x plane
y plane
case 1, random offsets, max = 10 µm. (new) x plane
y plane
case 1, random offsets, max = 20 µm. x plane
y plane
case 1, random offsets, max = 20 µm. (new) x plane
y plane
case 1, random offsets, σ = 5 µm. x plane
y plane
case 1, random offsets, σ = 10 µm. x plane
y plane
case 1, random offsets, σ = 20 µm. x plane
y plane
case 1, SP4 with x offset in gaussian distribution, σ = 20 µm. x plane
y plane
case 1, SP4 with x and y offset in gaussian distribution, σ = 20 µm. x plane
y plane
case 1, SP1 with x offset in gaussian distribution, σ = 20 µm. x plane
y plane
case 1, SP1 with x and y offset in gaussian distribution, σ = 20 µm. x plane
y plane
case 1, offset uniform distributed between -100 µm and 100 µm. x plane
y plane
case 1m, offset uniform distributed between -100 µm and 100 µm. x plane
y plane
case 2, offset uniform distributed between -100 µm and 100 µm. x plane
y plane

Field scan when alignment errors do exist
adjust ± 0.003T around nominal fields
sp1_x_error(µm) sp1_y_error(µm) sp4_x_error(µm) sp4_y_error(µm) ImpactT ImpactT ImpactT-V5.1-PSI-2 ImpactT-V5.1-PSI-2
3 0 0 2 x plane
y plane
x plane
y plane
5 3 -5 3 x plane
y plane
x plane
y plane
7 1 -1 1 x plane
y plane
x plane
y plane
-9 -9 7 -5 x plane
y plane
x plane
y plane
18 19 -6 1 x plane
y plane
x plane
y plane
39 64 -41 10 x plane
y plane
x plane
y plane




Last update:

Thomas.Schietinger@psi.ch