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