KIT – The Research University in the Helmholtz Association
Institute for Beam Physics and Technology (IBPT)
www.kit.edu
Status of FLUTE FLUTE, a linac-based THz source at KIT
Minjie Yan for the FLUTE collaboration
22-24.11.2017 Minjie Yan – Status of FLUTE
Institute for Beam Physics and Technology (IBPT)
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FLUTE overview
Final electron energy ~ 41 MeV
Electron bunch charge 1 - 3000 pC
Electron bunch length ~1 - 300 fs
Pulse repetition rate 10 Hz
THz E-Field strength up to 1.2 GV/m long. phase space:
RMS bunch length 3.2 fs
22-24.11.2017 Minjie Yan – Status of FLUTE
Institute for Beam Physics and Technology (IBPT)
3
status report last year
22-24.11.2017 Minjie Yan – Status of FLUTE
Institute for Beam Physics and Technology (IBPT)
4
now
status report last year
22-24.11.2017 Minjie Yan – Status of FLUTE
Institute for Beam Physics and Technology (IBPT)
5
Inauguration of FLUTE: 13.07.2017
http://www.ibpt.kit.edu/news_2017_7_KIT_press_release_FLUTE_inauguration_presidents.php
Photos: Markus Breig, KIT
22-24.11.2017 Minjie Yan – Status of FLUTE
Institute for Beam Physics and Technology (IBPT)
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FLUTE Status: Phase I
FLUTE hall
Laser THz Measure-
ment room
Control
room
Vacuum components
Laser
RF
Magnets & Diagnostics
SRR collaboration
22-24.11.2017 Minjie Yan – Status of FLUTE
Institute for Beam Physics and Technology (IBPT)
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Vacuum components status
Assembly finished
Partially evacuated: < 10-8 mbar
Photos: Markus Breig, KIT Photo: Laila Tkotz, KIT
22-24.11.2017 Minjie Yan – Status of FLUTE
Institute for Beam Physics and Technology (IBPT)
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Laser status 1/2
Laser transport of the 800 nm over 35 m onto the optical table in the
bunker
Prealignment of the last in-vacuum mirror with the cathode using a
laser tracker and an alignment laser almost finished
Measurement:
Image of the laser in the bunker
Courtesy: M.J. Nasse, T. Schmelzer
22-24.11.2017 Minjie Yan – Status of FLUTE
Institute for Beam Physics and Technology (IBPT)
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Laser status 2/2
In progress:
Purchase order of a larger, adapted optical
table for gun and SRR
Next step: THG on the table
e-
e-
Courtesy: M.J. Nasse, T. Schmelzer
22-24.11.2017 Minjie Yan – Status of FLUTE
Institute for Beam Physics and Technology (IBPT)
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RF-system status 1/2
All RF components assembled and tested
Klystron RF test finished
Klystron output ready for gun commissioning
Photos: Pawel Wesolowski, KIT
22-24.11.2017 Minjie Yan – Status of FLUTE
Institute for Beam Physics and Technology (IBPT)
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Power supply
50 kV, 200 mA Pulse forming network 525 nF,
21.5 mH
Pulse envelope is 4.5 us (NO LLRF feedback loop)
Transformer tank 1:14.5
and 45 MW klystron
RF-system status 2/2
Courtesy: N. Smale
22-24.11.2017 Minjie Yan – Status of FLUTE
Institute for Beam Physics and Technology (IBPT)
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Magnets and Diagnostics
No. Installation EPICS integr.
Magnets
Solenoid 1
Quadrupole 1
Dipole 1 ( )
Steerer 2
Diagnostics
Screen station 2
ICT 1 in progress
Faraday cup 1 in progress
BPM 3 in progress
22-24.11.2017 Minjie Yan – Status of FLUTE
Institute for Beam Physics and Technology (IBPT)
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SRR collaboration 1/4
Space for gun laser preparation,
diagnostics & SRR THz generation
Split-ring resonator vacuum chamber Image adapted from: J. Fabiańska et. al., Sci. Rep. 4, 5645 (2014)
THz
pulse
UV
pulse
E(t) in SRR gap
electric field
fs laser
<2 ps
LiNbO3
3n
n
THz streaking of the
electron bunch for
temporal diagnostics
First experiment planned
at FLUTE
22-24.11.2017 Minjie Yan – Status of FLUTE
Institute for Beam Physics and Technology (IBPT)
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Beam kick / % Resonant f / THz
SRR cubic gap 100 0.3
Slotted tube 60 0.5
Tube (com.) 420 0.5
SRR plate 180 0.5
SRR collab. 2/4:
Simulation results for various structures
Beam “kick” normalized to SRR (typical ranges 1 to 10 keV / c)
Courtesy: M. Dehler, M. Yan
22-24.11.2017 Minjie Yan – Status of FLUTE
Institute for Beam Physics and Technology (IBPT)
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Vacuum chamber
Design at PSI
Manufacturing at PSI
Installation at KIT
SRR collab. 3/4:
Task status PSI
22-24.11.2017 Minjie Yan – Status of FLUTE
Institute for Beam Physics and Technology (IBPT)
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THz generation
Design at Bern
Set-up & test at Bern
Installation at KIT
SRR structures
0 2 4 0
2
4
x (mm) y (
mm
)
Profile measured with
FLUTE laser at KIT
(laser lab)
Focused THz beam image
0 2 4
0
2
4
S (
arb
. u
.)
S (arb. u.)
3 2 1 0
0 1 2 3 4·103
4·103
Horizontal Vertical FWHM
0.92 mm 1.15 mm (at 0.3 THz) 1 mm
pixel size
indicators
SRR collab. 4/4:
Task status Uni Bern
22-24.11.2017 Minjie Yan – Status of FLUTE
Institute for Beam Physics and Technology (IBPT)
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R.W. Assmann, M. Felber, K. Flöttmann, M. Hoffmann,
H. Schlarb
H.-H. Braun, M. Dehler, M. Divall, R. Ganter, N. Hiller,
R. Ischebeck, M. Moser, L. Stingelin, V. Schlott, C. Vicario
A big Thanks to our partners from the
FLUTE collaboration:
… and others who are not in the photo
22-24.11.2017 Minjie Yan – Status of FLUTE
Institute for Beam Physics and Technology (IBPT)
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22-24.11.2017 Minjie Yan – Status of FLUTE
Institute for Beam Physics and Technology (IBPT)
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Progresses always accompanied by problems…
Untight RF waveguide: MAX lab borrowed us some spare parts
Cathode RF finger, cathode positioning
Laser jumps suddenly to TEM11 mode
