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PITZ overview: the PITZ portfolio
Frank Stephan for the PITZ teamContent:• The PITZ collaboration• A) photo injector R&D in ST3 “ps/fs electron and photon beams”
• R&D program agreed with and co-funded by XFEL• Progress on generating 3D ellipsoidal beams• Operation experience with Gun 4.6 • Gun quad corrector studies• Design of gun 5• Bunch shaping with dielectric lined waveguides• Generation of THz radiation
• B) Plasma Activities @ PITZ in ST4 “Novel acceleration concepts”• Beam driven plasma acceleration activities:
- Self modulation experiments- Transformer ratio experiments
• Laboratory Astrophysics preparations
See scientific highlight talk
Frank Stephan for the PITZ team | PITZ overview: the PITZ portfolio | LAOLA workshop | 27. 6. 2017 | Page 2
> Founding partners of PITZ:
DESY, HH & Z (leading institute)
HZB (BESSY) (A. Jankowiak): magnets, vacuum
MBI (S. Eisebitt): cathode laser
TU Darmstadt (TEMF, T. Weiland, H. DeGersem): simulations
> Other national partners: Hamburg university :
- most PhD students; - HGF-Vernetzungsfond; - generation of short pulses- plasma experiments
HZDR: - BMBF-PC-laser-project between MBI, DESY and HZDR, unitl ~2009; - collaboration between HZB, HZDR, MBI andDESY in SC-gun-cluster
> International partners: IAP Nizhny Novgorod + JINR Dubna :
3D elliptical laser pulses, THz radiation
INFN Frascati + Uni Roma II (L. Palumbo, M. Ferrario): TDS and E-meter pre-studies
INFN Milano (C. Pagani): photocathodes
INR Troitsk (L. Kravchuk): CDS, TDS, Gun5
INRNE Sofia (D. Tonev, G. Asova): EMSY + personnel
LAL Orsay (A. Stocchi): HEDA1 + HEDA2
STFC Daresbury (S. Smith, B. Militsyn): phasespace tomography
Thailand Center of Excellence in Physics(T. Vilaithong, Ch. Thongbai): personnel
YERPHI (V. Nikoghosyan) + CANDLE (V. Tsakanov, B. Grigoryan), Yerevan : personnel
PITZ Collaboration Partners ( formal contract signed )
Frank Stephan for the PITZ team | PITZ overview: the PITZ portfolio | LAOLA workshop | 27. 6. 2017 | Page 3
R&D program agreed with and co-funded by XFEL
> Funding is planned from ~mid 2017 on and current planning horizon is until 2021 , yearly update (no major changes)
> A) From XFEL operations budget:- Support of XFEL operation : 4 weeks of PITZ operation for dedicated measurements
+ 1 physicist for working on improving pulsed guns - e.g. gun quad corrector studies, different operation modes (charges, bunch length), time resolved and emittance
measurements , emission studies, test of unified procedures , diagnostics, stabilization , llrf and laser components, …
- Option ( on request, ~1 year in advance): gun construction and conditioning (16 weeks)
> B) From XFEL R&D budget:- Advanced photo cathode laser shapes: 2 weeks of PITZ operation for generic R&D on
ellipsoidal electron bunches- ultimate beam quality at different cathode gradients, … e.g. measurements (emitt., LPS, µ-bunching ) for different
laser shapes
- Developments towards CW guns : 4 weeks of PITZ operation for basic CW gun research (e.g. beam dynamics at CW gun gradients , green cathodes ) + 1 physicist investigating a 216 MHz NC CW gun and supporting SRF gun activity
- Experimental beam dynamics studies at CW gun gradients e.g. emission properties, thermal emittance , optimumbeam quality using different laser shapes , …
- Studies towards green cathodes dark current, emission properties, thermal emittance, optimum beam quality usingdifferent laser shapes and gun gradients, …
- Physical design of 216 MHz NC CW RF gun + buncher system RF + beam dynamics simulations, beamlineoptimization, …
Frank Stephan for the PITZ team | PITZ overview: the PITZ portfolio | LAOLA workshop | 27. 6. 2017 | Page 4
Under operation at PITZ:> Hamamatsu SLM> Laser integrated into PITZ laser beam line> Synchronization with RF realized with uTCA> Beam shaping studies begun (SLM masks)> Electron beam measurements with regular
shaped ELLA pulses (starting Dec.2016now)
Progress on generating 3D ellipsoidal beams with the laser systemfrom the Institute of Applied Physics (IAP, Nizhny No vgorod)
Spatial Light Modulator ( SLM) based pulse shaper
Manipulations on spectrum of a linear chirped pulseLaser pulse shape reconstruction from spectrograph measurements
F2
M(Ω)
F1f f f f
Upcoming upgrade at PITZ:> Pharos-20W-1MHz frontend laser delivered should solve most of laser related problems > 3D volume Bragg gating (DSF funds) postdoc will start 1.8.2017
X
Tim
e
Recent electron beam measurements at PITZ (0.5nC)
E-beam TDS-streaked~parabolic shape
Issues limiting current performance:> Laser beam transport (transverse size)> Oscillator + disc amplifier performance:
Synchronization (<10kHz) Stability (pointing and intensity jitter, long term
drift) Spectrum pulse too short
> Pockels cell (contrast, flatness)> …
, , ∙ , 1.06
ELLA laser at VC2
Frank Stephan for the PITZ team | PITZ overview: the PITZ portfolio | LAOLA workshop | 27. 6. 2017 | Page 5
Operation experience with Gun 4.6
PMT
e-det
PG
pump
dir.cpl.
valvestemp.
PMT PMT
PMT
PMTse-det e-det
IR IR
PMT
IGP
IGP
IGPIGP
dir.cpl.
dir.cpl. dir.cpl.
dir.cpl.
temp.
temp.
temp.
temp.
PMT – Photomultiplier tube
e-det – Electron detector
IR – Infrared sensor
IGP – Ion getter pump
(pressure reading)
PG – Pressure gauge
radiuschanged
nose removed
air air
> Features of the Gun 4.6 setup Gun 4.6 with new type of cathode spring holder
design (watchband-reloaded)
two conditioned DESY-type windows for the 2-window setup (as in 2011)
T-Combiner with optimized RF design for best window positioning for reflections
> Operation at 6.5 MW, 650µs, 10Hz: Cathode spring design and
2 RF vacuum window solution seem to work reliably ! Problem with inserting cathode probably related to
malfunctioning/damage/misalignment of z-manipulator NEXT: - Gun4.6 quick restart , run until Oct.2017 ( XFEL)
- then Gun4.5 with 2 Thales windows
Frank Stephan for the PITZ team | PITZ overview: the PITZ portfolio | LAOLA workshop | 27. 6. 2017 | Page 6
Gun quad corrector studies (measurements 2017)• BSA = 1.2 mm• Charge = 500 pC• Gun power = 6.5 MW
• Booster power = 3 MW• Gaussian Laser temporal profile: ~11.5 ps• Bunch length (TDS) = 15.8 ps
Machine parameters:
No Gun Quads applied : Gun Q1 = 0A / Gun.Q2 = 0A With Gun Quads : Gun Q1 = -0.6A / Gun.Q2 = -0.5A
Transverse beam profile
X phase space
Y phase space
Transverse beam profile
X phase space
Y phase space
• The gun quad currents were selected to deliver the most round beam spot at High1Scr1 and High1Scr4 simultaneously
No Gun Quads With Gun Quads
x y xy x y xy
Emittance, mm·mrad
1.11 0.78 0.93 0.82 0.84 0.83
Beam RMS size, mm
0.46 0.32 0.28 0.32
α -0.99 0.39 0.06 -0.01
β 4.85 4.37 3.18 3.24
γ 0.41 0.26 0.32 0.31
No Gun Quads With Gun Quads
“rounder” and smaller emittance!
“rounder” beam
X&Y numbersare close
Frank Stephan for the PITZ team | PITZ overview: the PITZ portfolio | LAOLA workshop | 27. 6. 2017 | Page 7
> Gun 5 new features (see V. Paramonov et al., NIM A 854 (2017) 113-126.):
includes RF probe fine control of RF stability, allows symmetric power coupler (2 input arms)
improved water cooling and reduced deformation over RF pulse more reliable operation at high duty cycle
improved cell geometry reduced RF heating & surface field strength
Gun 5 for higher stability & reliability in technic al design
NX10I-DEAS
test piece
Technical design ongoing and experiments on test pieces started
Frank Stephan for the PITZ team | PITZ overview: the PITZ portfolio | LAOLA workshop | 27. 6. 2017 | Page 8
First Bunch Shaping Experiments with DLW at PITZ> In collaboration with CFEL (F. Lemery) and APC FNAL (P. Piot)
F. Lemery et al., Experimental demonstration of ballistic bunching with dielectric-lined waveguides at PITZ, IPAC 2017, WEPAB122
Measured Longitudinal Phase Space
E-beam current profile without (blue trace) with DLW (red trace), λ=1.03 mm; The peaks are consistent with the wavelength of the structure 3.3 ps.
Frank Stephan for the PITZ team | PITZ overview: the PITZ portfolio | LAOLA workshop | 27. 6. 2017 | Page 9
> Idea: Accelerator based THz (1) & electron diffraction source (2) for XFEL users
Tunable THz source for pump-probe experiments at XFE L + High flux e - diffraction source based on PITZ prototype
(2) Femtosecond e - diffractionv.s. X-ray: sub-pm wavelength, good spatial resolution ~106 higher scattering cross section, good for
thin or low density samplev.s. other MeV electron diffraction source: higher rep. rate & higher flux; trade flux for higher transverse coherence;new methodology: XFEL pump, electron probe;
PITZ gun
L-band linac(booster or buncher)
Sub-100 fse- diffraction
User sample chamber
>15 meter
(1) Linac based THz sourceAttractive features:• provides high power (high field)
Possible options:• Undulator SASE THz FEL• Other, e.g. transition, diffraction, synchrotron, edge radiation
Challenges:• Phase locking (CEP stability) for field driven dynamics• Short bunches (bunch compression) for single-cycle radiation
Simulated energy of the radiation pulse
100 µm (3 THz)
~3 mJsynchronized
with XFEL train structure
Current status:• First electron beam measurements for SASE THz FEL option
were done• CTR experiment station is under realization• Seeding options under study
Basic PITZ parameters:• bunch length: sub ps to 22 ps• bunch charge: sub pC to > 5 nC• max Pz ~ 24MeV/c• pulse train structure similar to XFEL
Complementary tool for XFEL
user to get a full picture of the
ultrafast atomic world!
• tunability of radiation• polarization control• clean production of
the radiation invacuum
H. QianM. Krasilnikov
Frank Stephan for the PITZ team | PITZ overview: the PITZ portfolio | LAOLA workshop | 27. 6. 2017 | Page 10
> Beam driven plasma acceleration activities:
Self modulation experiments
High transformer ratio experiments
Highlight talk
Frank Stephan for the PITZ team | PITZ overview: the PITZ portfolio | LAOLA workshop | 27. 6. 2017 | Page 11
Laboratory Astrophysics
> Idea: find parameter scaling so that astrophysical phenomena can be investigated in the laboratory
> Currently: DESY Strategy Fund project to demonstrate Bell‘s instability
Collaboration between 3 different divisions: THAT (Martin Pohl), PITZ (Frank Stephan) and FLA (Jens Osterhoff)
Simulation study / exploring experimental possibilities; best case: first experimentsin 2018
> Bell‘s instability: Amplification of magnetic fields in a plasma, induced by cosmic rays
> This could be part of the mechanism of cosmic particle accelerators
Frank Stephan for the PITZ team | PITZ overview: the PITZ portfolio | LAOLA workshop | 27. 6. 2017 | Page 12
Current Work
> 1) PIC simulations for laboratory conditions
Preliminary results: Need
• Low plasma density (1013 or less)• Low beam energy (<10 MeV)• Long electron bunches (best DC) with at least mA current
> 2) Study if these conditions can be provided by PITZ
> So far: challenging, but no show stoppers found yet
extensive simulationshave started and willbe continued
Frank Stephan for the PITZ team | PITZ overview: the PITZ portfolio | LAOLA workshop | 27. 6. 2017 | Page 13
Summary & Outlook
> There is a very rich and scientifically and technically interesting program ongoing at PITZ, with substantial support from XFEL.
> Several topics are of high relevance for different groups, at DESY andworldwide.
> Largest part of activity is in ST3: fs/ps electron and photon beams
> But also significant activity in beam driven plasma acceleration seehighlight talk
> Laboratory Astrophysics experiments are under preparation