Summary from TTF2 Working Group

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Summary from TTF2 Working Group Jean-Paul
Carneiro, Markus Koerfer DESY, Hamburg TESLA
COLLABORATION MEETING ORSAY, 7-Sept-2004
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TESLA COLLABORATION MEETING WORKING GROUP
TTF2 LAL ORSAY, 7-SEPT-04 Morning (9H00? 10H30,
11H00?12H30) 9H00 ? 10H30 Carneiro
Cryogenics Installations TTF2 in 2004 and Future
Plans Lange (20) TESLA Cavities in
the VUV-FEL LINAC Modules Kostin
(20) Status of the TTF-II vacuum system
Zapfe (20) Power Supplies for TTF2 and
Pulse Cable for Modulator Eckoldt
(30) 11H00 ? 12H30 Koerfer Status RF
System Choroba (15)
Commissioning of the LLRF for the VUV-FEL
Simrock (10) RF Control Improvement for
TTF II with low latency FPGA feedback Jezynski
10 VUV-FEL Controls Rehlich
(15) TTF 2 Diagnostics Status and
Availability of Toroids, BPMs, Castro (15)
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Afternoon (14H00? 16H00, 16H30?18H00) 14H00?
16H00 Carneiro TTF-VUV FEL Optical Systems
Castellano (15) Photoinjector Laser
Operation and Cathode Performance
Sertore (20) Beam based alignment, Dark
current and Thermal emittance Miltchev
(20) Status of Emittance Measurements at the
TTF/VUV-FEL Injector Honkavaara (20) First
Measurements on HOM-Based Alignment in the TESLA
Cavities Baboi (20) 16H30? 18H00 Koerfer
Improvements in LLRF control algorithms and
automatio Brandt (20)
TTF2-Time-Of-Flight Measurements
Kollewe (20) TTF2 Start-Up Simulations
Yurkov (20) TTF2 commissioning
strategy Castro
(10) Discussion about commissioning
Prepared but not presented (available on the
web) Attempt of measurement of linear
dispersion Golubeva (10) Commissioning
445-MeV Optics of the TESLA Test Facility Linac
Balandin (10) Velocity bunching simulations
for TTF2 Carneiro (10)
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Cryogenics Installations TTF2 in 2004 and
Future Plans

• -Assembly and installation of Module M2 (old
  type II)
• for Position ACC1
• -Commissioning of the new TTF2 set up with
• 5 Cold Accelerating Modules
• -Cool down, operation and tests of the new TTF2
  set up
• -Shut down June-04 until September-04
• -Cryogenic operation possibillities/redundancies
• Future
• -Preparation and assembly Module M6 (new type 3)
• -Fermilab buildts 3rd Harmonic Module (3.9GHz)
• -Cryogenic supply for Superconducting Magnetic
  Energy Storage SMES
• -Module Teststand
• -Update Cold Box Hall 3 (2 new screw compressors
  already in operation)

R. Lange
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TTF2 since March 2004
Automated Cryo-operation for TTF2-Linac
Linac Transfer
From/to CB HERA or CB Hall 3
Fermilab Feedbox
BCBTL2
BCBTL1
ACC2 Transferl
ACC1 Transferl
VB
VB
Endcap
ACC5 M5
ACC4 M4
ACC1 M2
ACC2 M1
ACC3 M3
BC2
BC3
Overview 21-Mar-04 Start cool down 28-Mar-04
4.3K/1.1bar 29-Mar-04 2 K / 31mbar 07-Jun-04
Shut down, but modules
stay cold at 4.3K/1.1bar 01-Sep-04 End of shut
down
GUN
Cryo losses static Watt Total Module 40/80K 1
300 74 4.3K 3201.6g/s 13 2.0K
21 lt3.5
R. Lange
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TESLA Cavities in the VUV-FEL LINAC Modules
D. Kostin
7
Modules Operating Gradients
ACC3
ACC4
ACC5
ACC2
ACC1
D. Kostin
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Cavities _at_ ACC1
EP cavity
D. Kostin
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EP Cavities
(AC72 is installed in ACC1)
D. Kostin
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S. Choroba
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S. Choroba
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S. Choroba
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S. Choroba
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S. Choroba
15
S. Simrock
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S. Simrock
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K. Zapfe
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K. Zapfe
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K. Zapfe
20
K. Zapfe
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K. Rehlich
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K. Rehlich
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K. Rehlich
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TTF 2 Diagnostics Status andAvailability of
Toroids, BPMs,
Prepared by D. Nölle
P. Castro
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STATUS

• Installation of diagnostics is completed
• exception BPM electronics
• BPM electronics available by end of 2004 (first
  boards maybe in November).
• For the commissioning use 20-15 TTF1 electronics
  (DESY Frascati units)
• Not useful for undulator (lt- Electronics
  container inside the tunnel)
• Problem Orbit tuning is not possible to required
  precision
• in the collimator
• in the undulator

P. Castro
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TTF/VUV-FEL Photon DiagnosticsStatus and
Availability
Prepared by R. Treusch
P. Castro
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Availability of VUV FEL diagnostics
Parameter Detector(s) Online available
Intensity Profile thermopiles, PtSi photodiodes, MCPs no no limited now
Intensity Position Gas Ionisation Detector YES April 2005
Spectrum Grazing incidence spectrometer (tunnel) no now (Commissioning)
Spectrum VLS Grating Spectrom. YES mid/end 2006
Timing Streak camera YES April 2005
Timing Auto-/Cross-Correlators YES ? (experimental stage)
P. Castro
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TTF-VUV FEL Optical Systems
LNF Frascati L. Cacciotti M. Castellano G.
Di Pirro O. Giacinti R. Sorchetti
Roma 2 L.Catani E. Chiadroni A.Cianchi M.
Raparelli
DESY K. Honkavaara
M. Castellano
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Total Camera Number
18 Standard Optical System 3 Gun Camera 4 Fixed
magnification (1 BC2 3 Bypass) 2 Diffractors
All of them are working
M. Castellano
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M. Castellano
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K. Honkavaara
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K. Honkavaara
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K. Honkavaara
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K. Honkavaara
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D. Sertore
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D. Sertore
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D. Sertore
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Beam based alignment, Dark current and Thermal
emittance measurements J-H.Han,M.Krasilnikov,V.Mi
ltchev, PITZ, DESY, Zeuthen

• Beam based alignment
• Laser alignment
• Solenoid alignment
• Dark current
• Thermal emittance

V. Miltchev
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Beam Based Alignment Conclusions

• Beam based alignment (BBA) of the gun can be
  done in two consequent steps
• 1. Alignment of the laser on the cathode
• 2. Solenoid alignment
• Beam based laser alignment at PITZ is a
  well-established procedure. To implement it at
  TTF a calibrated camera at double diagnostic
  cross screen is required
• Mechanical beam line misalignment complicates
  the BBA, introducing an additional uncertainty
• Some steps in the gun solenoid alignment have
  been done. It is complicated by an uncertainty
  introduced by mechanical beamline misalignment,
  not perfectly aligned laser on the cathode and
  some uncertainty in machine parameters (rf field
  amplitude and absolute phase, solenoid
  calibration). For further alignment more detailed
  study is needed.

V. Miltchev
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Modeling of the Field Emission Source
Well conditioned (less dark current)
Edge of the Mo plug 8000 macro particles
Edge of Cs2Te film 2000 macro particles
Cs2Te flim (5 mm ?) 2000 macro particles
Mo plug (16 mm ?) 8000 macro particles
V. Miltchev
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FC1 and FC2 (42 MV/m)
Faraday cup 1
Faraday cup 2
Main reason of the mismatch between measurement
and simulation beamline misalignment and the
effect of steerers. ? lower energy part of the
dark current is filtered out.
V. Miltchev
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Thermal emittance measurements

• The final goal is to estimate the average kinetic
  energy Ek of the emitted photo electrons.
• Assuming isotropic emission
• An estimate for could be given by
  measuring the transverse
• emittance vs. laser spot r.m.s. size s,
  provided that eRF, eSC 0
• Use very small charge (2-3 pC) and short laser
  pulses (6-8 ps FWHM)
• Use single slit scanning and/or solenoid scan to
  measure emittance
• Check the dependence of the transverse emittance
  on applied electric field on the cathode

V. Miltchev
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Thermal emittance measurements
Transverse emittance for different r.m.s. laser
spot sizes measured with the single slit scanning
method at a charge of about 3pC and an
accelerating gradient at the cathode of 32 MV/m.
V. Miltchev
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Thermal emittance measurements
Summary

• The transverse emittance was measured for very
  low charge of 2-3 pC and short laser pulses of
  6-8 ps FWHM
• The scaling of transverse emittance with laser
  spot r.m.s. size was measured
• The average kinetic energy Ek of the emitted
  photo electrons was estimated to be 0.8 0.1eV
• Thermal emittance was measured as a function of
  the applied field a the cathode
• An increasing of the thermal emittance with
  accelerating gradient was observed

V. Miltchev
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N. Baboi
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N. Baboi
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N. Baboi
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M. Kollewe
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M. Kollewe
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M. Kollewe
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M. Kollewe
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M. Kollewe
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M. Yurkov
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M. Yurkov
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M. Yurkov
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M. Yurkov
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TTF2 commissioning strategy
P. Castro
P. Castro
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BEAM COMMISSIONING STEPS - SUMMARY

• re-commissioning of gun injector
• setup cavity phases ACC2-5 ? beam energy
• setup bunch compression
• setup beam linear optics, optimize orbit
• commissioning of diagnostics

1st beam (bypass)
3 weeks

• setup collimation
• emittance measurements and optics matching
• beam-based alignment in undulator section
• commiss. of photon diag. with spon. emission

FEL 30 nm 1 bunch
10 weeks
Saturation 6-100 nm

• commissioning of FEL diagnostics
• study of FEL beam, compression schemes, etc.
• establish reproducible settings, etc.

8 weeks
P. Castro