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WP10.6 Advanced Photocathodes Developement
DESY Jacek Sekutowicz
HZB Thorsten Kamps
HZDR Jochen Teichert
IOE MUT Henryk Fiedorowicz
IPJ Robert Nietubyć
BNL John Smedley
MBI Ingo Will
TJNAF Peter Kneisel
Introduction
Pb DAC
Motivation
To construct an injector for high quality electron beam of parameters dedicated for specific applications. High bunch charge for pulse FEL and high average current for ERL and CW FELs.
The part of the proposed programme is an improvement of CARE and Eucard achievements - Pb/Nb films for SRF injector, another part is an expansion to the field of DAC photocathodes and constrution of unique laser for Pb cathode excitation.
Hobicat at HZB, May 2011
IPJ, September 2011
UV laser
Organisation
deposition, treatment and structural studies
injector cavity
measurementslaser
IOE
(MBI)
IPJ HZB HZDRDESY
PbDAC
design & engineering
SR tests injector tests
Advanced Photocathodes Developement
Baseline programme and fundamental deliverables
New deposition system built and operating, Pb samples layers without laser flattening.Thickness and cleanliness improvementdesign → construction → samples deposition
Prototype M9 IPJ
Pb sample layers deposited and flatten with the laser (optimized procedure), Post-deposition microdroplets removal and morphology improvement, filtering elimination
Measurements of electron beam emitted from a plug sample photocathodes morphology influence on the performance
Structural studies of Pb/Nb films. XRD, PES,
Report M12 IPJ, IOE
Report M18 HZB
IPJ
Report M24 HZDR
Pb
Pb spot deposited on the e-gun cavity wall, flatted with the laser, QE and emittance measured in cold testSpot flattening → Installation → cleaning → Q measurements → QE measurements → e-beam diagnostics
Measurements at HZB
Injector cavity preparationImproved design in term of electromagnetic field, additional cavity enables more tests
Construction → comissioning → baseline Q tests → Pb Q test
Laser 206 nm, 20 ps, 100 kHz, 1 W, An unique and dedicated laser providing UV pulses of short duration, high energy and high repetition rate is unavoidable to operate high average current an injector furnished with Pb photocathode
Fundamental generator → Amplifier + puls shaping → Harmonics converter → assembly → comissioning → installation at Hobicat
Baseline programme and fundamental deliverables
Report M18 DESY
Prototype M30, IOE
(MBI)
Report M36 HZB,
DESY, IPJ, IOE
Pb
Design and engineering of cathode insert with diamond amplifier
SR test of DAC cellCell will be provided by BNL and tested at BESSY II beamline at HZB
Report M36 HZB, HZDR
Report M30 HZB BNL
Report M18 HZDR, HZBDAC
Baseline programme and fundamental deliverables
Test DAC in DC/SRF gun setup at HZDR and/or HZB
Test will be done at HZDR or HZB
Costs classification
deliverable
kEUR at 100%
kEUR at75%.
kEUR at50%
Pb
New deposition system IPJ 100 100 100
Pb sample layers deposited and flatten
IOEIPJ,
1515
520
520
Structural studies of Pb/Nb films. XRD, PES,
HZBIPJ
2015
520
520
Measurements of electron beam emitted from a plug sample photocathodes
HZDRIPJ
1010
515
515
Injector cavity preparation DESY 119 100 100
Laser 206 nm, 20 ps, 100 kHz, 1 W
HZBIOE
50582
0496
0260
Pb spot deposited on the e-gun cavity, cold tests
DESYHZBIOEIPJ
40301727
4015025
4015025
DAC
Design and engineering of cathode insert with diamond amplifier
HZBHZDR
80100
6085
6085
SR test of DAC cell ? HZB 41 15 15
Test DAC in DC/SRF gun setup at HZDR and/or HZB
HZBHZDR
4674
2156
2156
Costs classification
deliverablekEUR at 100%
kEUR at75%. Implications
kEUR at50% Implications
Pb
New deposition system 100 100 Construction costs are ridgid 100
Pb sample layers deposited and flatten
35 25 Only annealing, pulse ablation is cancelled
25
Structural studies of Pb/Nb films. XRD, PES,
35 25 Less number of samples, only those annealed
25
Measurements of electron beam emitted from a plug sample photocathodes
20 20 The easiest way to study the performance
20
Injector cavity preparation 119 100 Preliminary photocathode deposition and tests measurements will not be possible before the final implementation at Hobicat. A risk rises significantly
100
Laser 206 nm, 20 ps, 100 kHz, 1 W 632 496 λ ≤ 215 nm, τ = 20 ps, no pulse shaping, f = 100kHz Pav = 1 WThe lack of pulse shaping deteriorates e-beam quality by the energy spread and reduces the bunch charge.
260 λ = 215 nm, τ = 30 ps, no pulse shaping, f = 20kHz, Pav = 0.5 WLong pulses and low repetition preclude the high average power tests. In such conditions only partial tests are possible. The system would require substantial reconstruction to be operated in FEL linacs
Pb spot deposited on the e-gun cavity, cold tests
114 80 Shorter beamtime available for final tests at Hobicat
80
DAC
Design and engineering of cathode insert with diamond amplifier
180 145 Less number of prototypes for lab and SR tests
145
SR test of DAC cell 41 15 Compromises in the transport vessel to get DAC inside SR beamline endstation
15
Test DAC in DC/SRF gun setup at HZDR and/or HZB
120 77 Test at one station only 77
1396 1083 837 (60%)Σ