EDMS No. 888499 Photoinjector General + Photocathodes presented by Konrad Elsener (CERN-AB)
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Transcript of EDMS No. 888499 Photoinjector General + Photocathodes presented by Konrad Elsener (CERN-AB)
![Page 1: EDMS No. 888499 Photoinjector General + Photocathodes presented by Konrad Elsener (CERN-AB)](https://reader031.fdocuments.in/reader031/viewer/2022032611/56649e795503460f94b78608/html5/thumbnails/1.jpg)
EDMS No. 888499
Photoinjector General +
Photocathodes
presented by Konrad Elsener (CERN-AB)
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EDMS No. 888499
Acknowledgements (PHIN)
We acknowledge the support of the European Community-Research Infrastructure Activity under the FP6 “Structuring the European Research Area” programme (CARE, contract number RII3-CT-2003-506395).
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EDMS No. 888499
Outline
Overview Photocathodes: Status + Outlook
(photocathode for CLEX) PHIN in CTF2 Summary
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EDMS No. 888499
Overview
LASER
RF GUN
RF equip.
Photocathode
“Photoinjector”
bunched
electron
beam
Cs2Te
UV
…cf. next two talks…
G. McMonagle
(yesterday)
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EDMS No. 888499
Photocathodes
cf. presentation by R. Losito, 17 Jan. 2007
HIGHLIGHT end of 2006:
Photocathode No. 166 produced (after > 3 years interruption)
Cs-Te cathode, co-evaporation,
Quantum Efficiency > 6%
very detailed description of No. 166: CTF3-Note-089
many thanks to Eric Chevallay
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EDMS No. 888499
Photocathodes – No. 167
HIGHLIGHT 2007:
Photocathode No. 167 produced 29 November
(Cs-Te cathode, co-evaporation)
Quantum Efficiency Lifetime
measured during 1000 hours
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EDMS No. 888499
0
2
4
6
8
10
12
14
16
0 200 400 600 800 1000 1200
time [h]
Qua
ntum
Eff
icie
ncy
[%]
data taken in DC-gun, 80 kV (-> 8 MV/m)
29 Nov. 2007 Xmas break 9 Jan. 2008
CTF3 specs
(drive beam)
Photocathodes - No. 167
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EDMS No. 888499
manipulator
DC- gun
preparation
chamber
transport
carrier
~ 1.4 m
Photocathodes – No. 167
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EDMS No. 888499
basic unit: Cu “plug”
on the “arm” inside
the transport carrier:
up to 4 plugs
Photocathodes - No. 167
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EDMS No. 888499
Photocathodes
Process Control and Reproducibility (A. Barbiero and E. Chevallay)
- cleanliness / UHV vacuum
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EDMS No. 888499
H2
CO
N2
N
CH4
O
H2O
...
a long period of improvements, pumping, leak testing, baking-out, leak testing,
repair, pumping, baking out, ...
vacuum before cathode preparation: < 3x10-11 mbar
residual gas analysis in preparation chamber (29 Nov. 2007)
Photocathodes - vacuum
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EDMS No. 888499
Photocathodes – film thickness
Process Control and Reproducibility (A. Barbiero and E. Chevallay)
- cleanliness / UHV vacuum
- film thickness monitoring (Te, not Cs)
-> new stylus profilometer, calibrated
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EDMS No. 888499
Photocathodes - film thickness
Te films on
quartz substrate
new Stylus Profilometer
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EDMS No. 888499
Photocathodes – film thickness
cross-check of Stylus Profiler using a calibrated sample* (Rank Taylor Hobson)with 3 grooves, 24 nm each
solid lines: =24 nm
dashed line: =26 nm
Result:
Profilometer intrinsic error < 2 nm
* sample on loan from CERN-TS/MME (W. Vollenberg)
0.5 mm
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EDMS No. 888499
Photocathodes – transfer arm
Process Control and Reproducibility (A. Barbiero and E. Chevallay)
- cleanliness / UHV vacuum
- film thickness monitoring
-> stylus profilometer, calibrated
- possibility of cathode chemical analysis (X-ray Photoel. Spectr.)
-> new, smaller transfer arm (for 1 plug)
(collaboration with team of M. Taborelli / TS-MME)
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EDMS No. 888499
Photocathodes – transfer arm
(attached to preparation chamber) (courtesy A. Barbiero)
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EDMS No. 888499
Photocathodes – plug surfaces
Process Control and Reproducibility (A. Barbiero and E. Chevallay)
- cleanliness / UHV vacuum
- film thickness monitoring
-> stylus profilometer, calibrated
- possibility of cathode chemical analysis (XPS)
-> new transfer arm
- reproducible “plug” surface
-> test programme on surface preparation + analysis
(work in progress - No. 166 and No. 167 are very different)
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EDMS No. 888499
photocathode for CLEX
Preparation chamber for CLEX
(ex-CTF2 Probe-Beam)
Cs + Te sources (no co-evaporation);
1 quartz thickness monitor (DN 100 flange)
manipulator arm
(position for “plug”)pumping
port
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EDMS No. 888499
“CTF2” (south)
photoemission
laboratory
“CTF2”
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EDMS No. 888499
“CTF2” - status
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EDMS No. 888499
Acknowledgments
Nathalie Lebas: expert help with the laser
Arnaud Brielmann: expert help with controls
and interlocks
(for equipment safety)
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EDMS No. 888499
Summary + Outlook
Photoemission Laboratory:
ready for production of cathodes Cs-Te cathode No. 167: ready for PHIN work in progress to improve reproducibility near future: CLEX cathode
continue contributions to PHIN in “CTF2”
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EDMS No. 888499
spare slides
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EDMS No. 888499
spare slides
8 Nov. 2007
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EDMS No. 888499
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EDMS No. 888499
PHIN overview
RF Network
Laser Beam Line0.37mJ / mPulse
2332 mPulses
Electron Beam2.33 nc / mPulses
Transportcarrier
3 GHz RF gunE = 85 MV/mU = 5.6 MeV
I = 3.5 ACs2
Te
cath
QE
= 3
%
Photocathodepreparation
chamber
Under the responsibility ofCLF-RAL
Under the responsibility ofLAL - Orsay
Under the responsibility ofCERN
Under RAL responsabilitywith CERN collaboration
Total efficiencyIROUT UVcath = 3.6 %
KLYSTRON3 GHz - 30 MW
Freq. X 4 l =
262 nm
Power Amplifier : DPSSL3-pass x 5
200 ms ; Ptrain = 15 kWl = 1047 nm ; 10.3 mJ / mPulse
Pulse width 10 psRep. Rate 5 - 50 Hz
Master oscillatorl = 1047 nm f = 1.5 GHzP > 0.2 W
W/mPulse > 0.13 nJ
Pulse shaping and stabilization
Phase coding
3 GHz RF source
Pre-amplifierl = 1047 nmPCW = 10 W
W/mPulse = 6.7 nJ
1.5 GHz
3 GHz
High Q Laser
First Amplifier : DPSSL3-pass x 300
400 ms ; Ptrain = 3 kW
2 mJ / mPulse
Pulse width 10 psRep. Rate 5 - 50 Hz
High Q Laser
Phase coding+ amplification