Guns Simulations Big Computers

Guns and Codes

Nicole Neveu

Illinois Institute of TechnologyArgonne National Laboratory

nneveu@anl.gov

June 12, 2018

N.Neveu ANL, IIT

USPAS Fundamentals, June 4-15, 2018

Guns Simulations Big Computers

Outline

GunsSourcesPhotoinjectors

SimulationsCodesPIC Results

Big Computers

N.Neveu ANL, IIT

USPAS Fundamentals, June 4-15, 2018

Guns Simulations Big Computers

GunsSourcesPhotoinjectors

SimulationsCodesPIC Results

Big Computers

N.Neveu ANL, IIT

USPAS Fundamentals, June 4-15, 2018

Guns Simulations Big Computers

What’s a gun?

A few key parts are needed:

Cathode (Source of particles)

Focusing (usually solenoids)

Vacuum (strict for electron machines w/ semiconductors)

Accelerating field

https://www.lhc-closer.es/taking_a_closer_look_at_lhc/0.proton_source

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USPAS Fundamentals, June 4-15, 2018

Guns Simulations Big Computers

Sources

Sources of particles: Cathodes

The particles have to come from somewhere:

metals and semiconductors

gas

filament

Source: AWA-ANLN.Neveu ANL, IIT

USPAS Fundamentals, June 4-15, 2018

Guns Simulations Big Computers

Sources

Thermionic CathodesA filament is heated up until electrons are emitted.

Sources: https://www.sciencedirect.com/science/article/pii/S0168900213014381#f0005https://nau.edu/cefns/labs/electron-microprobe/glg-510-class-notes/instrumentation/

N.Neveu ANL, IIT

USPAS Fundamentals, June 4-15, 2018

Guns Simulations Big Computers

Sources

PhotocathodesNeeds a laser

Photoelectric effect

https://phys.org/news/2013-02-black-gold-enabling-bright-high.html

N.Neveu ANL, IIT

USPAS Fundamentals, June 4-15, 2018

Guns Simulations Big Computers

Photoinjectors

AWA-ANL Gun

RF Photoinjector, 1.5 cell

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USPAS Fundamentals, June 4-15, 2018

Guns Simulations Big Computers

Photoinjectors

AWA Gun fields

0.0 0.1 0.2 0.3 0.4 0.5Z [m]

60

50

40

30

20

10

0El

ectri

c Fi

eld

[MV/

m]

0.4

0.3

0.2

0.1

0.0

Mag

netic

Fie

ld [T

]

Electric field, EzMagnetic field, Bz

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USPAS Fundamentals, June 4-15, 2018

Guns Simulations Big Computers

Photoinjectors

Gun Types

DC Guns

Bunch compression usuallyrequired

RF Guns

Energy chirp, but bunched

https://www.classe.cornell.edu/~hoff/LECTURES/08S_688/08S_688_080225.pdf

N.Neveu ANL, IIT

USPAS Fundamentals, June 4-15, 2018

Guns Simulations Big Computers

GunsSourcesPhotoinjectors

SimulationsCodesPIC Results

Big Computers

N.Neveu ANL, IIT

USPAS Fundamentals, June 4-15, 2018

Guns Simulations Big Computers

Simulations

Simulations give help with design and prediction of accelerators.Two main types of simulations:

PIC: Particle in Cell

Model particles individually

Envelope

Use matrices to look at envelope behavior

Historically, envelope codes were first. Now computing resourcesare good enough to use PIC in more situations.

N.Neveu ANL, IIT

USPAS Fundamentals, June 4-15, 2018

Guns Simulations Big Computers

Codes

Some Envelope Codes

These codes do matrix multiplication, and use input beamparameters to find Twiss parameters around a beam line.

MADX - http://mad.web.cern.ch/mad/

Elegant (also a PIC code) -https://beta.sirepo.com/elegant#/simulations

Accelerator Toolbox (AT) -https://www.slac.stanford.edu/grp/ssrl/spear/at/

TRACE - http://laacg.lanl.gov/laacg/services/download_trace.phtml

N.Neveu ANL, IIT

USPAS Fundamentals, June 4-15, 2018

Guns Simulations Big Computers

Codes

PIC Codes

PIC = Particle in Cell

Distribute particles on a grid and solve equations numerically.

Particle-Particle Forces (space charge)

E&M Forces

Apertures

Draw some things on the board....Meshes, particle push, etc.

N.Neveu ANL, IIT

USPAS Fundamentals, June 4-15, 2018

Guns Simulations Big Computers

Codes

Some PIC codes for beam line modeling...Parmela -http://laacg.lanl.gov/laacg/services/serv_codes.phtml

ASTRA - http://www.desy.de/~mpyflo/

GPT - http://www.pulsar.nl/gpt/

OPAL - https://gitlab.psi.ch/OPAL/src/wikis/home

Synergia - https://web.fnal.gov/sites/Synergia/SitePages/Synergia%20Home.aspx

Bmad - https://www.classe.cornell.edu/bmad/

G4beamline -http://www.muonsinternal.com/muons3/G4beamline

WARP - http://blast.lbl.gov/blast-codes-warp/

IMPACT - http://blast.lbl.gov/blast-codes-impact/

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USPAS Fundamentals, June 4-15, 2018

Guns Simulations Big Computers

Codes

Some PIC Codes cont..

Elegant (also a PIC code) -https://beta.sirepo.com/elegant#/simulations

N.Neveu ANL, IIT

USPAS Fundamentals, June 4-15, 2018

Guns Simulations Big Computers

Codes

PIC Code Comparison

Feature ASTRA GPT OPAL

Windows 3 3 7

Mac 3 3 3

Linux 3 3 3

Open Source 7 7 3

Parallel 7* 7* 3

Autophase 3 7 3

Adaptive Time Step 7 3 7

3D Space Charge 3 3 3

Wakefields 3 7* 3

CSR 7 7* 3

* features available on request or in specific versions.N.Neveu ANL, IIT

USPAS Fundamentals, June 4-15, 2018

Guns Simulations Big Computers

PIC Results

PIC Results: Statistics, beam parameters w.r.t. bunch.

N.Neveu ANL, IIT

USPAS Fundamentals, June 4-15, 2018

Guns Simulations Big Computers

PIC Results

Beam Line Modeling, High Charge

Gun

S1 S2

L1 L2 L3 L4 L5 L6

QuadsDrive Line

Kicker

Septum

DipoleMechanical considerations:

1m between kicker and septumfor separation ≥ 50mm in septum.

1.8m between septum and dipolefor separation ≥ 0.5m of beam lines.

15cm between quads for easy installation.

0.3m between quads and PETS for yag screen.

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USPAS Fundamentals, June 4-15, 2018

Guns Simulations Big Computers

PIC Results

PIC Results: High Charge 40 nC

0 5 10 15 20 25s [m]

0.000

0.002

0.004

0.006

0.008

0.010

0.012

x,y

x

y

kickerquadsPETSbending elements

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USPAS Fundamentals, June 4-15, 2018

Guns Simulations Big Computers

PIC Results

PIC Results: Real Space

−10.0 −7.5 −5.0 −2.5 0.0 2.5 5.0 7.5 10.0

Z [mm]

−15

−10

−5

0

5

10

15

X[m

m]

Longitudinal Distribution After Gunz = 0.4 [m]

0

5

10

15

20

25

−20 0 20X [mm]

−30

−20

−10

0

10

20

30

Y[m

m]

M=250, FWHM=1.5ps:DYAG1

5

10

15

20

25

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USPAS Fundamentals, June 4-15, 2018

Guns Simulations Big Computers

PIC Results

PIC Results: Phase Space

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USPAS Fundamentals, June 4-15, 2018

Guns Simulations Big Computers

PIC Results

Optimization

Accelerators have many free parameters: magnets, phases,dimensions, etc. Optimization is an alternative to brute force andhand tuning.

0.8 1.0 1.2 1.4 1.6 1.8

Bunch Length [mm]

0

50

100

150

200

250

300

350

Em

itta

nce

[µm

]

Random Sample

Approx. Pareto Front - Model Based

Approx. Pareto Front - GA gen 25

Approx. Pareto Front - GA gen 500

0 25 50 75 100 125 150 175 200

Function Evaluation

−0.02

0.00

0.02

0.04

0.06

wǫ x

+(1

−w

)σ

z

w = 0.0

w = 0.1

w = 0.2

w = 0.3

w = 0.4

w = 0.5

w = 0.6

w = 0.7

w = 0.8

w = 0.9

w = 1.0

N.Neveu ANL, IIT

USPAS Fundamentals, June 4-15, 2018

Guns Simulations Big Computers

GunsSourcesPhotoinjectors

SimulationsCodesPIC Results

Big Computers

N.Neveu ANL, IIT

USPAS Fundamentals, June 4-15, 2018

Guns Simulations Big Computers

Computing resources available to you:LCRC-ANL: Bebop

ORNL: Titan, Summit

FNL: Local resources

ALCF-ANL: Theta, Mira

NERSC-LBNL: Edison, Cori

ORNL: Titan, Summit

N.Neveu ANL, IIT

USPAS Fundamentals, June 4-15, 2018

Guns Simulations Big Computers

Computer Jargon / typical hardware / software.

Linux, KNL’sslurm, torque, batch jobs

Let’s do a demo? Sirepo and bebop.

N.Neveu ANL, IIT

USPAS Fundamentals, June 4-15, 2018