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Παραγωγή, διάγνωση και δυναμική σωματιδιακών δεσμών υψηλής έντασης από συμβατικούς και υπεραγώγιμους επιταχυντές Georgios Kourkafas INP Demokritos, 22.11.2018 Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators

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Folie 1συμβατικος και υπεραγγιμους επιταχυντς
Generation, diagnosis and dynamics
normal- and superconducting accelerators
> Self introduction
Outlook
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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
Self Introduction – Further education
(Basic Accelerator Physics Theory)
Theoretical and Experimental Quantum Physics
Nuclear and Elementary Particle Physics
> 2013: CERN Accelerator School (CAS), Trondheim, Norway
(Advanced Accelerator Physics)
(Plasma Wake Acceleration)
(Numerical Methods for Analysis, Design and Modelling of Accelerators)
Georgios Kourkafas | 22.11.2018 Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators
Experience from LHC (CERN)
Performance Evaluation Section
> 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:
Investigations on Orbit Correctors (I)
Collimator TCP.D6L7.B1
Event evolution
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Event evolution
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Georgios Kourkafas | 22.11.2018 Generation, 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)
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Investigations on Orbit Correctors (II)
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Magnet name MCBV.11L1.B1 MCBCV.9L1.B2 MCBCV.7L1.B3
kick [rad] 1.19E-05 0 1.11E-05
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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
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Investigations on Orbit Correctors (II)
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Investigations on Orbit Correctors (II)
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Investigations on Orbit Correctors (II)
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Investigations on Orbit Correctors (II)
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Investigations on Orbit Correctors (II)
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Investigations on Orbit Correctors (II)
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Investigations on Orbit Correctors (II)
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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
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Dif 1389-1393
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Experience from PITZ (DESY)
to low-energy e- for radiation sources
> PhD Student (06.2011 – 10.2015)
the matching of the transverse phase space
– operation of the PITZ facility as shift leader
(conditioning, commissioning, beam diagnostics)
PITZ facility
7 MeV/c
Bucking solenoid
Main solenoid
2 – 25 ps laser pulses
< 4 nC bunch charge
PITZ facility
> Electron bunches
< 4 nC bunch charge
PITZ facility
2 – 25 ps laser pulses
< 4 nC bunch charge
PITZ facility
2 – 25 ps laser pulses
< 4 nC bunch charge
> Several diagnostics for the longitudinal and transverse phase space:
3 slit-scan stations (EMSYs) and 1 phase space tomography [PST] module
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PITZ facility
2 – 25 ps laser pulses
< 4 nC bunch charge
> 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
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+ Improved SNR
(→ less sensitive to short-term machine instabilities)
− Requires beam matching and space-charge treatment
for optimal performance
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Beam tomography & matching with space charge
> Beamline components:
> Matching requirements // strategies:
@ each screen (∝ rotation angles) // extend
MAD by scaling beam parameters with
smooth-approximation space-charge theory
M2
M3
M4
> Beamline components:
2. Matching quadrupoles for the necessary
entrance beam parameters
> Matching requirements // strategies:
@ each screen (∝ rotation angles) // extend
MAD by scaling beam parameters with
smooth-approximation space-charge theory
βx,y = 1 m, αx,y = ±1 // SC software (HZB) to
match and compensate emittance growth…
Beam tomography & matching with space charge
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(~15 min) / 500 pC, 21 MeV/c, 12 ps \ (~3.5 h)
Beam matching with space charge:
simulation benchmarking
Beginning of matching (slit scan)
Beam matching with space charge:
simulation & measurement
2 m downstream, 4 quads in between (slit scan)
Beam matching with space charge:
simulation & measurement
Beam matching & tomography with space charge:
simulation & measurement 8 m downstream, 9 quads in between (tomography)
X
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Experience from bERLinPro (HZB)
> Postdoc (10.2015 – present)
> Work summary:
- feasibility studies of ultrafast electron diffraction
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Max. beam energy (MeV) 50
Max. beam current (mA) 100 (77 pC / bunch)
Frequency (GHz) 1.3
Bunch length (ps) < 2 ps (100 fs)
Beam losses << 10-5 @ 100 mA
SRF Photoinjector
• CsK2Sb photocathode
• 1.4-cell SRF cavity (klystron)
• ΔE = 44 MeV
2 for acceleration (klystrons)
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
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Phase
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Photocathode transfer system
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bERLinPro photoinjector characterization
QE at 9.5 MV/m e- 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
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Superconducting solenoid magnet
• thermal conduction
• electrical insulation
• mounting complexity
Manufactured by external
company – designed, tested
Transverse deflecting RF cavity
• bunch duration
y
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e-
E-field
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Ultrafast electron diffraction / microscopy
Material research with fs-short MeV e- which probe samples at MHz rates
• motivation: examine time-resolved
biological & gas-phase samples
collimation, samples, detector
Georgios Kourkafas | 22.11.2018 Generation, diagnosis and dynamics of high-intensity particle beams from normal- and superconducting accelerators
Summary & outlook
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, …
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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,