AWAKE workshop, CERN, April 9th-11th, 2014 Steffen Döbert, BE-RF

AWAKE electron source

New Electron Source WP at CERN

Base Line Scenario

Simulations

Diagnostics

Questions and Issues

Conclusions

Layout of AWAKE Experiment

Layout of Electron sourceTo be developed in the future

Base line scenarioBase line

• Use PHIN gun and equipment (convert to copper cathode ?)• Klystron and Modulator from CTF3• Get booster from Cockcroft/Lancaster collaboration (specs from

CERN) ?• Additional equipment needed (solenoids, vacuum, wave guides,

girders)• Diagnostics, PHIN, CERN, INFN (to be defined)• Beam dynamics simulations, CERN ,Cockcroft ?• Integrated test in CTF2 in 2016, external help welcome• Installation and commissioning into CNGS area in 2017, external help

welcomeAlternative, upgrade

• Look for alternative gun, Califes, Cockcroft/Lancaster, INFN ? (goal will be ultimate beam performance, tiny emittance, ultra short bunches)• Evaluate performance, impact and cost

Work package responsibilities

Tasks Responsible

RF power CERN, Gerry McMonagle

GUN CERN, Steffen, Eric Chevallay

Booster STFC, Graham Burt ?

Laser CERN, Valentin Fedosseev

Instrumentation CERN, Lars Jensen

Mechanical design CERN, Nicolas Chritin

Magnets CERN, Jeremie Bauche

Vacuum CERN, Jan Hansen

Controls CERN, Marine Gourber-Pace

Integration CERN, Fred, Ans Pardons

Commissioning CERN, Steffen, Chiara

Simulations CERN,STFC, Steffen, Oznur Mete ?

Interlocks, Safety CERN, Rui Nunes

Be aware this list is certainly incomplete and preliminary

Ion Pump ?

AWAKE – INJECTOR MODULE

RF Gun

Beam

Direction

Ion PumpSupport Pedestal

Synthetic Granite Girder

Booster Linac 1m long

YAG

Quadrupole Magnet

Slit

Horizontal and Vertical Corrector Magnet YAG

Proposal by STFC Daresbury

AWAKE electron sourceschematic

Length ~ 4 m

FC

E, DE

MS

BPR

Laser +Diagnostics

RF GUN

Emittance

Incident, Reflected Power and phase

Spectrometer

Corrector

MTV

VPI

FCT

AcceleratorMTV,

Emittance

Matching triplet

BPR

BPR

Incident, Reflected, transmitted Power

Klystron

A,f

Awake electron beamrequirements

Parameter Phase 1 Phase 2

Beam Energy 13-16 MeV 20 MeV

Energy spread (rms) 0.1 %

Bunch Length ~ 4 ps < 1 ps

Laser/Rf synchronization 1 ps 0.1 ps

Free Repetition Rate 10 Hz

Synchronized repetition rate 0.03 Hz

Beam Focus Size < 250 mm

Divergence < 3 mrad

Normalized Emittance 2-5 mm mmrad 0.5 mm mrad

Bunch Charge 0.2 nC 1 nC

Awake simulationsPhin gun, 20 MV/m structure, 0.1 nC, 1 mm 3 ps laser

-50 0 50 100 150 200 2500

0.1

0.2

z

Bea

m S

ize

x (c

m)

-50 0 50 100 150 200 2500

0.1

0.2

z

Bea

m S

ize

y (c

m)

0 50 100 150 2000

1

2

3

z

Em

i x

0 50 100 150 2000

1

2

3

z

Em

i y

0 50 100 150 2000

10

20

z

En

erg

y (M

eV)

0 50 100 150 2000

1

2

3

z

bu

nch

len

gth

(p

s)

Awake simulations

Phin gun, 20 MV/m structure, 0.2 nC, 1 mm laser

0 50 100 150 2000

1

2

3

z

Em

i x

0 50 100 150 2000

1

2

3

z

Em

i y

Awake simulationsPhin gun, 20 MV/m structure, 0.2 nC, 1 mm laser,

1 ps laser

-50 0 50 100 150 200 2500

0.1

0.2

z

Be

am S

ize

x (

cm

)

-50 0 50 100 150 200 2500

0.1

0.2

z

Be

am S

ize

y (

cm

)

0 50 100 150 2000

1

2

3

z

Em

i x

0 50 100 150 2000

1

2

3

z

Em

i y0 50 100 150 200

0

10

20

z

En

erg

y (M

eV)

0 50 100 150 2000

1

2

3

z

bu

nch

len

gth

(p

s)

Awake simulations

Phin gun, 20 MV/m structure, 0.1 nC, 0.5 mm laser

0 50 100 150 2000

0.5

1

z

Em

i x

0 50 100 150 2000

0.5

1

z

Em

i y

Awake simulations

Phin gun, 20 MV/m structure, 0.1 nC, 0.25 mm laser

0 50 100 150 2000

0.5

1

z

Em

i x

0 50 100 150 2000

0.5

1

z

Em

i y

Many variants are possibleClear laser and beam parameter specification are needed for the

simulationsShould define reference scenarios for the simulations

Booster structure

Some rough numbers1 m long constant gradient structuref= 2998.55 MHzQ ~ 15000r/Q ~ 70 MWDV= 15 MVTf= 280 ns, 2a ~ 2 cmPo = 11 MW

PHIN gun needs about 10 MW for 85 MV/m

Roughly 30 MW needed to power the injector (one klystron)

Laser diagnostics: laser power, position, virtual cathode, micro pulse length

RF diagnostics: rf power signals, rf phase

Beam instrumentation

Instrument How many Resolution Precision

BPMs 3 50 mm ? ?

Phase monitor 1 ps ? ?

Screen 3 20 mm ? ?

Multi slit 1 < mm mrad ? ?

FCT 1 pC ? ?

Faraday Cup 1 pC ? ?

Spectrometer 1 10 keV ? ?

Streak Camera 1 < ps ? ?

Define rough commissioning scenario, what do we measure where and how

Klystron Issues Transport: Study of transport and possibility to

exchange klystron in situ has to be done, likely a

local lifting device is needed

Synchronisation: 3 GHz synchronized signal is

needed as well as a number of timing triggers

Safety: The modulator contains Oil together with

high voltage, the waveguide may contain SF6

A risk assessment has to be done to determine fire

protection measures !!

Remote control: We usually have access to those

klystron while running beam, likely need to improve

the remote control capabilities

Questions

A few question to trigger discussions:

1. Timing: How is it organised, beam, controls,

data acquisition

2. Controls: Guidelines for the control system,

hardware, FESA, data base

3. Experiment data taking: which information we

need synchronized, sampling rate (BPM’s

protons, electrons, Laser, spectrometer )?

4. Location of electronics for power supplies,

diagnostics and data acquisition

Rough time line2014 2015 2016 2017

Beam line design

Booster design

Infrastructure definition

Rough Integration

Detailed Component design and fabrication

Detailed integration

Infrastructure installation(Water, Power, Ethernet, klystron handling)

Installation and commissioningIn CTF2(may be not all hardware)

Infrastructure installation, electron source shielding, access system, racks

Installation of source and commissioningin AWAKE

Infrastructure and issues before installation:Water, power, Ethernet, klystron handling equipment, racks for electronics, electron source shielding, access system, laser beam line, alignment concept, commissioning concept, controls

Conclusions

New CERN work package for the electron source in

place

Many open questions we have to address in the

future

Beam requirements for first phase likely possible

with PHIN gun and booster

Some useful equipment should be available from

CTF3

Need detailed beam and laser specifications

Requirements for second phase challenging to fulfil

simultaneously

A lot of work ahead, help is very welcome

End

Awake electron beam work package reflections

Questions:

Access scenario, where can we go during experiment Location of power supplies, electronics, data acquisition, vacuum

equipment Location of klystron/modulator elements Transport of klystron/modulator items, crane for mounting klystron ? Safety requirements, restrictions Electron source housing, how does it look like Beam diagnostics, what has been done for the beam line yet, BPMs,

correctors Control system, beam, vacuum Water, electricity availability Clarify collaborations, with UK, Frascati ? Define time constraints, milestones

Single plasma cell @side injection

2 plasma cells/on-axis injection

Awake simulationsPhin gun, 20 MV/m structure, 0.01 nC, 0.5 mm laser

0 50 100 150 2000

0.5

1

z

Em

i x

0 50 100 150 2000

0.5

1

z

Em

i y