pitz shutdown 2007 - DESY

1

-J.Bähr, PITZ, Technisches Seminar, 3.Juli, 2007 1

PITZ Shutdown 2007

J.Bähr

PITZ, DESY

Technisches Seminar 3.Juli 2007


Outline• Outline1. Introduction2. Explanations: PITZ, XFEL, Emittance,…3. PITZ more detailed4. Shutdown: Why and what5. Manpower and coordination6. Outlook

2


1.Introduction- A long shutdown at PITZ is planned starting

from 20/08/2007 until beginning of November- Most modules of the vacuum beamline will be

dismounted and re-mounted in a new scheme - The Conditioning Test Stand (CTS) will be

mounted in the tunnel bearing gun 4.1- The rf system 1 will be re-organized for the

use of a 10 MW klystron- Many further tasks


2. Explanations: PITZ, XFEL, Emittance …

• What is that:• PITZ,XFEL,FLASH,emittance, laser, SASE,

space charge, electron gun…• What is the connection between:

– FEL and emittance– Emittance and space charge– A gun and a TV tube– PITZ and the XFEL,FLASH– …

3


Setup PITZ1.6 completed !transverseemittance

gunboosterquads

longitudinalphase space masks

Gun


PITZ• PITZ:“ Photo injector

Test Facility“• Test and optimize

electron sources forFELs: FLASH,XFEL

• X-FEL: European X-ray FEL project

• e-gun

4


„FEL-Microscope“• FEL: „Free Electron Laser“:

„Microscope“• Motivation!!!• Resolution R:

about wavelength R~ λfor microscopes

• The higher the beamenergy , the smaller

• better) the resolution R of the „microscope“

• c=νλ ,E=hv E=hc/λλ~1/E

• Resolution ~ λ~1/E

• Resolution of microscopes

Atoms~1 Angstr.3 GeVXFEL

Molecules~7nm500 MeV/200eV

FLASH

Big molecules

~O(10 nm)Magnifica-tion: 10**5

~70 keVElectronmicro-scope

Biologiccell

1 µm1 eV (light)Light micro-scope

ObjectResolutionEnergyElectron/photon

Device


FEL• FEL: Free electron laser :SASE principle

e-GunLinear accelerator Undulator: Magnetic structure

E-beam

Light/electro-magnradiation

Beam dump

SASE principle:„Self amplified radiation by stimulated emission“

PITZ

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The gun

• The gun:– Laser input port– Cathode– rf coupler– Solenoid magnets– Resonator– Vacuum tubes


Comparison of an e-gun and a TV tubeGun-TV

TV Gun

Bild Bild

Cathode thermal Photo effect acceleration Electro static Rf Voltage accel. ~4kV ~6 MV Electron energy ~4 keV

W=Q*U=1e*4kV 6 MeV

El. Field strength E=U/d=4kV/0.2m=20kV/m 60MV/m Deflection Electro static Dipole magnet (if

wanted visualisation TV screen + eye Flourescence screen

+ TV camera (no access)

radiation X-rays X-rays Create image deflection Move laser spot

6


Comparison between TV tube and an electron gun

Focusing using solenoids


Mis-unerstanding• If one does not consider the motivation and

the context one could assume:

• PITZ is a not effective designed, rather hugebuilt TV tube with enormous runningparameters, where one has no access and the TV program is not interesting for typicalcitizens and difficult to regard and onlyremotely because there is no accesspossible. The screen size is much too low(about 2“).

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FLASH• FLASH: Free electron LASer in Hamburg• (earlier TTF)

Brilliance: Photons in solid angle and per area unit pro wavelength intervall

Gun

LINAC Undulator

PITZ


Laser• LASER: „Light Emission by Stimulated Emission of

Radiation“• Characteristics of laser light:

1. High energy density :“parallel“ ray of light instead of divergent bundle

2. Coherence: phase relations between parts of the light ray: possibility of interference Holography

3. Monochromatic light: only one wavelength (visible-invisible)

Resolution R~ λ~1/E

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Electromagnetic spectrum

Resolution R~ λ~1/E


Emittance• Emittance :• Characteristic of electron

beam• For FEL small emittance

necessary!!!• Optimization of e-gun:

Minimalization of transverseemittance

• - EMSY: Emittancemeasurement system

• Emittance cannot beimproved after the source!!

• Emittance

• Divergent electron beam• ε : diameter * angle• ε = d * α in mm *mrad• Example : • Beam diameter : 1mm• Divergence α =0.05 °=

1mrad• ε = 1mm mrad

d

α


Emittance1. What emittance has been measured by

PITZ?2. What are the goals?3. World record?

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εx,y ~ (e- beam size) • (e- beam angular divergence)

Why injector so important ?What is emittance ?

Why it must be small ?

εn = 1 mm mrad

length of the undulator

εn = 2 mm mrad

εn = 4 mm mrad

Q = 1 nCoutp

ut p

eak

pow

er o

f th

e VU

V-FE

L @

6.4

nm

(G

W)

path length in the undulator (m)

VUV-FEL

peak power

• smaller emittance ⇒ new horizons: shorter wavelength,higher repetition rate

• XFEL goal: 0.9 mm mrad@injector = 1.4 mm mrad@undulator

εn = 1 mm mrad

outp

utpe

akpo

wer

of t

heXF

EL S

ASE

2@

0.1

nm

(GW

)

path length in the undulator (m)

εn = 2 mm mrad

εn = 3 mm mrad

peak current: 5 kAenergy spread: 2.5 MeV

XFEL

absolute numbers


Emittance• Emittance results:

0.8

1.2

1.6

2.0

2.4

2.8

3.2

320 322 324 326 328 330Imain, A

norm

. em

ittan

ce /

mm

mra

d ExEySQRT(Ex*Ey)measured @ PITZ:

p = 5.2 MeV/c

Q = 1 nCΦ = Φm

Ibuck = Imain * 0.075(100% rms projected emittance)

Results fromPITZ1: 2005 (Gun1) VUV-FEL13nm

XFEL

WR

VUV-FEL 6nm

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Emittance• Results 2006: Gun3.1

0,5

1,0

1,5

2,0

2,5

3,0

278 280 282 284 286 288 290Imain [A]

norm

. pro

ject

ed e

mitt

ance

[mm

mra

d]

Emitt(x)Emitt(y)ASTRA simulation


Setup PITZ1.6 completed !transverseemittance

gunboosterquads

longitudinalphase space masks

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Present layout of PITZ


PITZ• Simplified scheme

DDC

Rf-coupler

rf

Laser beam

E-gunDiagnostics

Booster cavityDiagnosticsBeam dump

Not in scale!!

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PITZ diagnostics

EMSYEmittance

Streak cameraBunch length

Spectrometer, dipole magnet

Beam energy

Faraday cup,ICT (Integratingcurrent transformer)

Charge

Screen station (TV),wire scanner

Beam:Profile, diameterDeviceMeasure


PITZ : Auxiliary system• Auxiliary systems• Vacuum• Photocathode laser and laser beamline• Cooling and climatization• Rf system: 2 Klystrons 5-10 MW,

modulators,…• Electronics• Controls

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PITZ history

PITZ history Year Gun Project

stage Remarks

1999 Decision directorate 2000 Construction 2001 Gun2 PITZ1 Commissioning 13/01/2002 Gun2 PITZ1 1st photoelectrons 2003 Gun2 PITZ1 Nov.:Gun2: HH 2004 Gun1 Dec.: upgrad 2005 Gun1 PITZ1.5 Upgrade, booster,

10MW klystron 2006 Gun1 PITZ1.6 57MW/m Gun3.1 Conditioning,

Characterization, Gun3.1 HH

2007 Gun3.2 PITZ1.6 Cond.,Charact. 2007 PITZ1.7


PITZ : The shutdown• Why?• Insert HEDA1: High energy

dispersive arm• Move booster downstream

(higher gun gradient)• Space for new CDS booster

(2008)• Minor change of sequence

of diagnostics elements• Prepare for PITZ 2

beamline 2008• Reconstruction of low

energy section (New DDC,..)

• Further tasks• Extension of laser hutch• New laser• New klystron 10MW for rf1• New technical interlock• Many small tasks

– TV system– Exchange YAG screen– EMSYs…– …

• PITZ1.6 PITZ1.7

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PITZ : The shutdown• Major changes in beam

line

GunBooster

Dipole Diagnostics Beam dump

Beam dump

Reconstructed low energy section

HEDA1

New HEDA1

HE diagnostics

modified

PITZ1.6

PITZ1.7


PITZ 1.6, PITZ 1.7PITZ 1.6

PITZ 1.7

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PITZ : The shutdown• Vacuum work:

– Dismount modules– CTS: Conditioning test stand:

Gun 4.1– Mount modules– Mount HEDA1– Reconstruction Low energy

section:• DDC• Dipole…

– ……– Parallel work of two teams New dipole HEDA1 – 180 grad


PITZ : The shutdown• RF group:• Reconstruction rf system1• Exchange klystron 5MW 10MW• Waveguides to CTS• Investigation of T-combiner• ………

• Electronics:• New technical interlock• Connect all new/moved components, tests• ……….

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PITZ : The shutdown• Controls• Control and data aquisition of elements of

reconstructed beam line and CTS• Control for new laser• Control of rf1• …..


PITZ : The shutdown• Technical infrastructure• Second crane in tunnel• Reconstruction laser hutch• New climatisation and cooling for laser and

laser hutch• Extension of cooling in tunnel new elements

and CTS• Upgrade of cooling systems• ……• Partially done by external firms

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PITZ : The shutdown• Laser hutch and laser• Extension of Laser: longitudinal profile: flat top with

rise and fall time of 1-2ps(10**-12)• Dismount laser• Extension of laser hutch• Climatisation, cooling , network, electric power• Cleaning• Mount new laser table• Mount new laser• Commissioning of laser: Beginning of November


PITZ : The shutdown• To do: Preparation and during shutdown• Sequence of work• Coordination between technical groups• Delivery of components

• End of shutdown• Start running with new laser in test mode:

Beginning of November

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PITZ : The shutdown• Flow chart


PITZ : Outlook• Outlook

• PITZ1.7 PITZ 2 : 2008• HEDA2 :July 2008• Tomography module (March 2008)• Magnets• Rf deflector as option• CDS Booster (Jan. 2008) • Beam dump : 2m³ concreteJuly 2008

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Comparison: PITZ1.6 ↔ PITZ2.0PITZ1.6:

PITZ2.0:

TESLA

CDS

• dipole is ready and tested,• technical design of dispersive arm ready,• parts in fabrication• installation starting August 20

• preliminary dispersive arm and beam dumpshave to be replaced by final components

• physics design is ongoing• sweeper under fabrication

tomography module + RF deflector arerealized depending on EU contracts,basic design available for both devices

tomography module + RF deflector arerealized depending on EU contracts,basic design available for both devices


Acknowledgement• Thanks to F.Stephan, S. Rimjaem and S.

Khodyachykh for providing transparenciesand photos

• Thanks to S.Niedworok and Chr. Iezzi for theposter

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PITZ shutdown 2007

• The end


0,8

1,2

1,6

2,0

2,4

2,8

3,2

320 322 324 326 328 330Imain, A

norm

. em

ittan

ce /

mm

mra

d ExEySQRT(Ex*Ey)measured @ PITZ:

p = 5.2 MeV/c

Q = 1 nCΦ = Φm

Ibuck = Imain * 0.075(100% rms projected emittance)

Results from PITZ1:

Particularities, Results from PITZ1• PITZ source must drive super conducting linac long pulse trains,

i.e. high average power, good stability

• XFEL goes to very short wavelength very good emittance required

0.2

0.3

0.4

0.5

0.6

0.7

800 1000 1200 1400 1600 1800 2000 2200

t / μsec

a.u. Forward powerReflected power

e.g. 800 µs

~ log(power)long RF pulse:

amplified output train

pulse train from the oscillator

10 Hz, 800µs, 1 MHz

long laser pulse train:

VUV-FEL, 6nm

XFEL

C

WR

measured @ VUV-FEL:

p = 127 MeV/c

Q = 1 nC

• regularly obtain 2.1 mm mrad(100% rms projected emittance)

• minimum 1.1 mm mrad(90% rms projected emittance)

PITZ gun installed at VUV-FEL in 2004

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first preliminary emittance results(not optimized yet !)

in operation: gun + booster 13.7 MeV/ccurrent booster: TESLA prototype

3,54

4,55

5,5

66,5

77,5

2 3 4 5 6 7 8

gun peak power, MW

Pmea

n, M

eV/c

38,4 44,3 49,6 54,3 58,7 62,7Ecath, MV/m

max. mean momentum ↔ gun power

goal: 60 MV/m

measured at PITZ2 (momentum of dark

current edge)

p = 12.8 MeV/c, Q = 1 nC,Φgun = Φmax_p, Φbooster =Φmin_dp

obtained at PITZ1

0

1

2

3

4

5

6

7

8

262 264 266 268 270 272 274 276 278 280 282Imain, A

Em

ittan

ce, [

mm

-mra

d]

Xemittance, measured

Yemittance, measured

Simulation (ASTRA)

First Results from PITZ2

Status: • new gun cavity (#3) installedand under conditioning now

• upgrade of beamline ongoing

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