Παραγωγή, διάγνωση και δυναμική

σωματιδιακών δεσμών υψηλής έντασης από

συμβατικούς και υπεραγώγιμους επιταχυντές

Georgios KourkafasINP Demokritos, 22.11.2018

Generation, diagnosis and dynamics

of high-intensity particle beams from

normal- and superconducting accelerators

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

> Self introduction

> p+ beam dynamics and diagnostics at LHC (CERN, Switzerland)

> e- beam dynamics and diagnostics at PITZ (DESY, Germany)

> e- beam generation and applications at bERLinPro (HZB, Germany)

Outlook

2

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

> Born in 1986, city of origin: Korinthos, Greece

> Diploma in Electrical and Computer Engineering in 2010 –

National Technical University of Athens, Greece

Focus in Electric Power and Biomedical Engineering

Thesis: Motion tracking in spin-tagging Magnetic Resonance Imaging (MRI)

using the Harmonic Phase (HARP) method. Collaboration with Urbana University, USA

Self Introduction – University education

3

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

Self Introduction – Further education

4

> 2011: Joint Universities Accelerator School (JUAS), Archamps, France

(Basic Accelerator Physics Theory)

> 2012: Physics Studies at Humboldt University, Berlin, Germany

Theoretical and Experimental Quantum Physics

Nuclear and Elementary Particle Physics

> 2013: CERN Accelerator School (CAS), Trondheim, Norway

(Advanced Accelerator Physics)

> 2014: CERN Accelerator School (CAS), Meyrin, Switzerland

(Plasma Wake Acceleration)

> 2018: CERN Accelerator School (CAS), Thessaloniki, Greece

(Numerical Methods for Analysis, Design and Modelling of Accelerators)

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

Experience from LHC (CERN)

> Technology Department –

Machine Protection and Electrical Integrity Group –

Performance Evaluation Section

> Technical Student (01.2010 – 02.2011)

> Work summary:

Data analysis, measurements and

calculations for improving LHC

operation and machine protection

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

> LHC has ~1000 superconducting Corrector Orbit Dipoles (COD), controlled

with an auto-feedback system

> Motivation: estimate the effect of a COD failure during collision optics

> Beam dynamics calculations suggest

a significant vertical misplacement:

> Beam loss is expected due to the failure

Investigations on Orbit Correctors (I)

Collimator TCP.D6L7.B1

Dy (sigma) 7.0

Collimator half gap (sigma)

9.8

6

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

Event evolution

Investigations on Orbit Correctors (I)

7

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

Event evolution

Investigations on Orbit Correctors (I)

with a σ/3 beam offset

8

Beam Position Monitor (BPM) reliability?

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

> Misbehaving BPMs & unnecessary / undetected orbit bumps are risky!

> How reproducible are the feedback settings of the corrector magnets?

Spot strong differences between consecutive fills:

> Calculate the effect of these single kicks on the beam orbit with MAD –

cross check calculations with BPM readings

Investigations on Orbit Correctors (II)

0.00E+00

2.00E-06

4.00E-06

6.00E-06

8.00E-06

1.00E-05

1.20E-05

0 5000 10000 15000 20000 25000

Dif

fere

nce

in k

ick

(rad

)

Position (m)

9

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

Investigations on Orbit Correctors (II)

-1400

-1200

-1000

-800

-600

-400

-200

0

200

400

600

BPM Readings - Difference between consecutive fills [μm]

Magnet name MCBV.11L1.B1 MCBCV.9L1.B2 MCBCV.7L1.B3

kick [rad] 1.19E-05 0 1.11E-05

10

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

Investigations on Orbit Correctors (II)

> Unwanted closed orbit bumps can be created by the feedback algorithm

> The evolution of the beam orbit might indicate undetected problems…

Magnet name MCBV.11L1.B1 MCBCV.9L1.B2 MCBCV.7L1.B3

kick [rad] (previous slide) 1.19E-05 0 1.11E-05

kick [rad] (closed bump) 9.96E-06 1.23E-06 1.30E-05

11

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

Investigations on Orbit Correctors (II)

12

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

Investigations on Orbit Correctors (II)

13

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

Investigations on Orbit Correctors (II)

14

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

Investigations on Orbit Correctors (II)

15

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

Investigations on Orbit Correctors (II)

16

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

Investigations on Orbit Correctors (II)

17

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

Investigations on Orbit Correctors (II)

18

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

Investigations on Orbit Correctors (II)

> A specific orbit corrector magnet was not powered for 5 consecutive fills

> Conclusion: the calculation of the beam orbit from the evolution of the

corrector magnets together with the monitoring of the BPM enhances the

redundancy of the LHC machine protection and optics reproducibility

> Resulted in the development of a software interlock which warns on

potential problems. It was later extended with a machine learning algorithm

-800

-600

-400

-200

0

200

400

600

800

BP

MS

W.1

R1.

B1

BP

M.1

2R

1.B

1B

PM

.24

R1.

B1

BP

M.3

2L

2.B

1B

PM

.20

L2

.B1

BP

M.8

L2

.B1

BP

MW

B.4

R2

.B1

BP

M.1

5R

2.B

1B

PM

.27

R2

.B1

BP

M.2

9L

3.B

1B

PM

.17

L3

.B1

BP

MW

E.5

L3

.B1

BP

M.9

R3

.B1

BP

M.2

1R3

.B1

BP

M.3

3R

3.B

1B

PM

.23

L4

.B1

BP

M.1

1L4

.B1

BP

MY

A.6

R4

.B1

BP

M.1

8R

4.B

1B

PM

.30

R4

.B1

BP

M.2

6L

5.B

1B

PM

.14

L5

.B1

BP

MS

Y.4

L5

.B1

BP

MW

T.B

6R

5.B

1B

PM

.17

R5

.B1

BP

M.2

9R

5.B

1B

PM

.27

L6

.B1

BP

M.1

5L

6.B

1B

PM

SE

.4L

6.B

1B

PM

.14

R6

.B1

BP

M.2

6R

6.B

1B

PM

.30

L7

.B1

BP

M.1

8L

7.B

1B

PM

.6L

7.B

1B

PM

.8R

7.B

1B

PM

.20

R7

.B1

BP

M.3

2R

7.B

1B

PM

.24

L8

.B1

BP

M.1

2L

8.B

1B

PM

SW

.1L

8.B

1B

PM

.11R

8.B

1B

PM

.23

R8

.B1

BP

M.3

3L

1.B

1B

PM

.21L

1.B

1B

PM

.9L

1.B

1

(μm

)

BPM readings – difference between consecutive fills

Dif 1389-1393

Dif 1408-1418

19

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

Experience from PITZ (DESY)

> From high-energy p+ for colliders

to low-energy e- for radiation sources

> PhD Student (06.2011 – 10.2015)

> Work summary:

– space-charge consideration

in the tomographic reconstruction and

the matching of the transverse phase space

– operation of the PITZ facility as shift leader

(conditioning, commissioning, beam diagnostics)

20

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

PITZ facility

7 MeV/c

Bucking solenoid

Main solenoid

Cs2Te

photocathode

RF cavity

laser

beam

e- beam

21

> Electron bunches for Free Electron Lasers

2 – 25 ps laser pulses

< 4 nC bunch charge

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

PITZ facility

> Electron bunches

2 – 25 ps laser pulses

< 4 nC bunch charge

< 25 MeV/c momentum

25 MeV/c

22

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

PITZ facility

> Electron bunches with high space-charge influence

2 – 25 ps laser pulses

< 4 nC bunch charge

< 25 MeV/c momentum

23

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

PITZ facility

> Electron bunches with high space-charge influence

2 – 25 ps laser pulses

< 4 nC bunch charge

< 25 MeV/c momentum

> Several diagnostics for the longitudinal and transverse phase space:

3 slit-scan stations (EMSYs) and 1 phase space tomography [PST] module

24

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

PITZ facility

> Electron bunches with high space-charge influence

2 – 25 ps laser pulses

< 4 nC bunch charge

< 25 MeV/c momentum

> Several diagnostics for the longitudinal and transverse phase space:

3 slit-scan stations (EMSYs) and 1 phase space tomography [PST] module

> Various applications require transverse beam matching. Due to the constantly

changing machine parameters (test facility), fast solutions are needed

25

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

+ Improved SNR

(→ suitable for low charges)

+ Simultaneous measurement of x-x’ & y-y’

(→ less sensitive to short-term machine instabilities)

− Requires beam matching and space-charge treatment

for optimal performance

Transverse Phase Space Tomography

linear

transport

matrices

beam

profile

monitors

> Tomography: algorithmic reconstruction of a sample

from its projections at different orientations

26

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

Beam tomography & matching with space charge

> Beamline components:

1. Quadrupoles apply phase-space transformations

between the projection screens [1..4]

> Matching requirements // strategies:

1. equidistant phase advance values (45º)

@ each screen (∝ rotation angles) // extend

MAD by scaling beam parameters with

smooth-approximation space-charge theory

2. Courant-Snyder parameters @ screen [1] →

βx,y = 1 m, αx,y = ±1

M2

M3

M4

S N

N S

gives instant result,

eliminates < 38°

mismatch

27

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

> Beamline components:

1. Quadrupoles apply phase-space transformations

between the projection screens [1..4]

2. Matching quadrupoles for the necessary

entrance beam parameters

> Matching requirements // strategies:

1. equidistant phase advance values (45º)

@ each screen (∝ rotation angles) // extend

MAD by scaling beam parameters with

smooth-approximation space-charge theory

2. Courant-Snyder parameters @ screen [1] →

βx,y = 1 m, αx,y = ±1 // SC software (HZB) to

match and compensate emittance growth…

Beam tomography & matching with space charge

28

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

(~15 min) / 500 pC, 21 MeV/c, 12 ps \ (~3.5 h)

Beam matching with space charge:

simulation benchmarking

29

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

Beginning of matching (slit scan)

Beam matching with space charge:

simulation & measurement

X

Y

Simulated Measured

30

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

2 m downstream, 4 quads in between (slit scan)

Beam matching with space charge:

simulation & measurement

X

Y

Simulated Measured

31

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

Beam matching & tomography with space charge:

simulation & measurement8 m downstream, 9 quads in between (tomography)

X

Y

Simulated Measured

> Tomographic

reconstruction

corrected by

< 20%

> Applicable to

compression

regions of

FELs,

plasma wake

acceleration,

injection lines

(EMMA), etc.

32

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

Experience from bERLinPro (HZB)

> From conventional to state-of-the-art technologies

> Postdoc (10.2015 – present)

> Institute for Accelerator Physics –

High Brightness Electron Beams Group

> Work summary:

- SRF photoinjector operation and coordination

- procurement of new hardware components

- feasibility studies of ultrafast electron diffraction

33

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

Max. beam energy (MeV) 50

Max. beam current (mA) 100 (77 pC / bunch)

Frequency (GHz) 1.3

Norm. emittance (mm∙mrad) 1 (< 0.5 in simulations)

Bunch length (ps) < 2 ps (100 fs)

Beam losses << 10-5 @ 100 mA

SRF Photoinjector

• CsK2Sb photocathode

• 515 nm laser, CW operation

• 1.4-cell SRF cavity (klystron)

• ΔE = 2 MeV

• SC solenoid

Merger section

• Injection to LINAC

• Bunch compression

• Emittance compensation

Main LINAC

• 3 × 7-cell SRF cavities (SSA)

• ΔE = 44 MeV

• Energy recovery

Splitter section

• Extracts decelerated beam

• Static widening, dynamic

sweep

Booster module

• 3 × 2-cell SRF cavities,

1 for RF chirp (SSA)

2 for acceleration (klystrons)

• ΔE = 4 MeV

Diagnostic line

Beam dump

bERLinPro: combine advantages of storage rings (high current) and linacs (low emittance) in

a power-efficient (100% duty cycle) small-scale accelerator

Recirculator

• TBA arcs for high

transmission and

tunability

Berlin Energy Recovery Linac Prototype

34

Phase

V

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

Photocathodetransfer system

SRF injector

Laser input

Diagnostic beamline

Superconducting RF photoinjector test stand

35

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

bERLinPro photoinjector characterization

Schottky scans Momentum scan at 10.2 MV/m

QE at 9.5 MV/me- beam measurements with:

• Cu cathode, 1.8 mm laser spot diameter

• UV laser with 12 kHz repetition rate

and 0.7 ps rms Gaussian pulses

• < 10 MV/m acceleration gradients

• measured properties: up to 1 nA current

(100 fC charge) and 1.2 MeV/c momentum

36

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

Superconducting solenoid magnet

Superconducting solenoid upgrade achieved:

• focusing properties for emittance compensation

• thermal conduction

• electrical insulation

• mounting complexity

Sophisticated 6D positioning with a hexapod,

beam based alignment with genetic optimizer

Manufactured by external

company – designed, tested

and measuremented at HZB

37

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

Transverse deflecting RF cavity

Tool for longitudinal beam diagnostics:

• bunch duration

• longitudinal phase space

• transverse slice emittance

Modified Cornel design manufactured

by external company, tested &

conditioned at HZB, installed at bERLinPro

y

z

e-

E-field

38

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

Ultrafast electron diffraction / microscopy

Material research with fs-short MeV e- which probe samples at MHz rates

• motivation: examine time-resolved

structural dynamics of surfaces, thin films,

biological & gas-phase samples

Feasibility study for HZB: beam dynamics and

collimation, samples, detector

39

Sample DetectorAdditions Collimator

SRF injector

Existing systems

Emittance

scanner

transverse

deflectorSpectro

meter

quads

z [m]

Bea

m s

ize

[mm

]

Cou

rte

sy

E.

Pa

no

fski

< 100 eV uncorrelated

energy spread

10 fC – 2 MeV

9 Å coherence

length 85 fs

bunch duration

60 μm·rad

transverse emittance

60nm WS2 on 500um Cu

Georgios Kourkafas | 22.11.2018Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

Summary & outlook

> From high-energy p+ colliders to low-energy e- sources,

accelerators require rigorous design, simulation, diagnostics,

characterization and machine protection to achieve optimal performance

> Range of applications expand constantly to new areas in

fundamental and material research

medical and industrial fields

> Interest tends to shift from large-scale facilities to small, cost-effective

machines: compact radiation sources, plasma wake acceleration,

ultrafast electron diffraction & microscopy, …

> Accelerators: “Extraordinary Tools for Extraordinary Science”!

40

THANK YOU FOR

YOUR ATTENTION

Achnowledgments:

CERN: R. Schmidt, M. Koratzinos

Cockcroft Institute: Kai M. Hock

Fritz Haber Institute: R. Ernstorfer, D. Zahn

DESY Zeuthen group: M. Krasilnikov, D. Malyutin, G. Vashchenko, F. Stephan

DESY Hamburg: M. Dohlus, B. Marchetti, J. Rossbach

HZB bERLinPro group: A. Matveenko, J.-H. Gwang, A. Jankowiak, T. Kamps,

G. Klemz, J. Kühn, A. Neumann, E. Panofski, M. Schmeißer, J. Völker

… and many more people which is difficult to include in one slide