RUPAC2006 Talk Weis PPT2003 - TU Dortmund

Universität Dortmund

2006 RUPAC, September 10-14, Novosibirsk

DELTADortmunder Elektronen-Speicherring-Anlage

Status of the 1.5 GeVSynchrotron Light Source DELTA

and Related Accelerator Physics Activities

Thomas Weisfor the machine and accelerator physics group

Dortmund UniversitySynchrotron Radiation Center

DELTA

2006 RuPAC, September 10-14, Novosibirsk




Content:• Machine Status• Insertion Devices• Orbit Control• EU-Cavity Beam Test• Instability Investigation• Machine Optics• Frequent Injction Mode• Summary

Dortmund UniversityGermany




DELTA

TGM

3

U250FZ Jülich

BL12: BL12: MethodsMethods (II): Soft X(II): Soft X--RaysRays

• Photoemission

• Photoelectron Spectroscopy

• Fermi-Surface Mapping

SAW

L=115,2 m

E=1.5 GeV




Full energy booster BoDo

full energy 1.5 GeVramped storage ring~ 0.1 Hz rep. rate




output energy = 75-80 MeVtotal length = 6.4 m (E = 12.5 MV/m)old SBTF-structure from DESY, Hamburg

Linear Injector

thermic electron gun50 keV, 2 A single bunch modefew bunch mode

3 GHz - klystron

40 MW loss power(ohmic losses in copper)

4 µsec RF-pulses@ a few Hertz repetition rate

A. Jankowiak, T. Weis et al., Proc 2000 EPAC (2000) 636



DELTADortmunder Elektronen-Speicherring-Anlageg

Single cell cavity @ DELTA

400 kV @ 500 MHzRF-power 50 kW cwloss power cavity 30 kWenergy transfer to beam 20 kW

single RF-DORIS-type500 MHz resonator




3 %coupling

16 nm rad @ 1.5 GeVhorizontal emittance

> 8 h multi bunch @ 1.5 GeV;> 20 min single bunch @ 542 MeV

beam lifetime

130 mA multi bunch @ 1.5 GeV;25 mA single bunch @ 550 MeV

nominal beam current

115.2 mcircumference

1.5 GeVmaximum beam energy

Maschine Parameters DELTA




User operation 2004/2005Operation 2004/2005

30 weeks (3000 h)

2000 h user operation.

1000 hours machine optimisation

and machine physics

Performance 2004/2005:

Average availability during 20 user weeks 94/89 %.

Max. beam current 120 mA.

Average lifetime ~ 7hrs

Availability during user weeks 200514.11.05

12.12.05

05.12.05

07.11.05

24.10.05

10.01.05

17.01.0531.01.05

11.04.0518.04.05

06.06.05

13.06.05 22.08.0517.10.05

19.09.05

26.09.05

101520253035404550556065707580859095

100

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

User weeks 2005

Ava

ilab

ility

[%

] 07.02.05

07.03.05

14.03.05

20.06.05

15.08.05

Performance 2006:

availability ~ 90%

Max. beam current 130 mA.

Average lifetime ~ 8-10 hrs

only minorvacuum openings




Insertion devices @ DELTA

U55 permanent magnet undulatorACCEL Instruments

SAW superconducting 5.3 T asymmetric multipole wigglerACCEL Instruments

U250 electromagnetic undulatorin house fabrication, also acting as FEL undulator




phot

ons/

s/m

A/m

m2 /

mra

d2 /

0.1%

BW

D. Schirmer et al., Proc. 2004 EPAC (2004) 2296




Parameter Dipole Wiggler (sym. mode)

Wiggler (asym. mode)

Magnetic field [T] 1.51 2.79 5.30 Critical current [A] @ 5T and 4.2 K 471 Number of periods 10 5 Beam stay clear [mm] 40 10 10

Horizontal opening angle θθθθ of radiation [mrad]

± 13 ± 25

Critical energie εεεεC [keV] 2.26 4.18 7.93

Critical wavelength λλλλC [Å] 5.49 2.97 1.56 Power P [W/mrad] 4.30 166.89 317.04 Vertical integrated photon flux @ εεεεC [photons/s/mrad/0.1%BW]

4.61·1012 6.86·1013 2.16·1013

Type of radiation (off-plane)

elliptical polarised

linear polarised high intensity

great fraction of circular polarisation at high intensity

Liquid He consumption ~ 12 liters/day with beam

Superconducting 5.3 T asymmetric multipole wiggler @ DELTA

first superconducting multpole wiggler worldwide

serving3 hard-X-raybeamlines

D. Schirmer, Int. J. Mod. Phys. 2B (1993) 644




under commissioningoperational end 2006

6 – 200 eVvalence band spectroscopy, Fermi-surface mapping

BL 12 / dipole(U Dortmund)

user operation55 - 1500 eVphotoemission spectroscopy, photoelectron diffraction

BL 11 / U55(U Dortmund)

under constructionoperational 2007

4 - 30 keVEXAFSBL 10 / SAW 1(U NRW)

user operation4 - 30 keVgrazing incidence X-ray diffraction,SAXS, XSW, inelastic X-ray

scattering

BL 9 / SAW 2(U Dortmund)

under commisioningoperational end 2006

2 - 30 keVmaterial science, EXAFS, diffractionBL 8 / SAW 3(U Wuppertal)

user operation5 - 400 eVphotoemission, spectroscopy BL 5 / U250(FZ Jülich)

user operationwhite beamX-ray fluorescence spectroscopyBL 2 / dipole(ISAS)

Present statusPhotonenergy

ExperimentsBeamline

SR-Beamlines @ DELTA

Wiggler Beamlines




Orbit Control and Stability

slow (0.1 – 1 Hz) globalorbit feedback system

method:

• singular valuedecompositionbased on a measuredorbit response matrix

M. Grewe et al., Proc. 2004 EPAC (2004) 2568

nrrrr

⋯

321

N correctors

M B

PM

s

= Rij




Orbit Stability

M. Grewe, thesis, Univ. Dortmund 2005

BPM 51

BPM 29

beam current

bea

mcu

rre

nt

bea

mo

rbit

dev

iatio

n[m

m]

location withhigh emphasis

floatingorbit




Orbit Stability

M. Grewe, thesis, Univ. Dortmund 2005

BPM 51

BPM 29

beam current

bea

mcu

rre

nt

bea

mo

rbit

dev

iatio

n[m

m]

• limited number of BPMs and correctors

• limited corrector strengths

• beam current (heat load) induced movement of vacuum chambers and quadrupols

• ongoing program concerning machine surveillanceand magnet repositioning and......

• ..... decoupling of quadrupoles and vacuumchambers (BPMs)

• nevertheless: reference orbit is reproducibleover months within +/- 250 µm horizontallyand +/- 150 µm vertically




Fast Beam andInstability

Investigationbunch train signal - 2 ns spacing

• filling pattern measurementbunch by bunch, turn by turn

• postmortem analysis of beam lossdue to coupled bunch mode- CBM – instabilities

• real time longitudinal CBM instability detectionDELTA BPM set up




Bunch by Bunch Beam Analysis

time [ns]

• sampling of BPM sum signalat 2 GS/s, bandwith 1 GHz

• oversampling technique using shiftbetween RF frequency and sampling frequency




I > 95 mA

I < 90 mAfilling pattern+ option to inject beam

into specific bucketsCoupled Bunch Mode No. 1 - 192

Osc

illa

tion

Am

plit

ud

e (d

egre

e)

real time (~ 1 s delay)analysis of longitudinal

coupled bunch CBM modes

J. Kettler et al., Proc. 2006 EPAC (2006) 1034




CBM Investigations @ DELTADORIS type cavity

I th≈ 75mA

I th≈35mA

E= 1.5 GeV T = 40-60 °C

I= 87mA

L1/L4

L16?

?

Osc

illa

tion

Am

plit

ud

e (d

egre

e)

Coupled Bunch Mode No. 1 - 192




Full understanding of filling pattern induced mode spectra

• 144/192 buckets filled• induced synchr. frequency

spread• Landau damping

Spectrum measured withDORIS cavity @1.5GeV

BLUE: measuredGREEN: theoretical

Osc

illa

tion

Am

plit

ud

e (d

egre

e)





CBM 22

CBM 52

ThresholdCBM 22

Oct. 18th 2005

ThresholdCBM 52

E= 1.5 GeV

CBM Investigations @ DELTADORIS type cavity with damping antennas

Osc

illa

tion

Am

plit

ud

e (d

egre

e)





EU-Project:Design, Construction and Beam Test of a n.c. HOM-damped

500 MHz-Resonator for Synchrotron Radiation Sources

1998 - 2004

Alu-model




The HOM-Damped EU-Cavity

Single Trapped Mode Resonator

Ridged waveguidesNose cones

Plunger

• Waveguide cut-off between fundamental and first HOM frequency

• HOM energy is dissipated in external RF loads

RF window

Cavity design: F.Marhauser & E.WeihreterBESSY, Berlin




F. Marhauser, E. Weihreter, Proc. 2004 EPAC (2004) 979Proc. 2002 EPAC (2002) 2172

Residual Longitudinal Impedance

Frequency [MHz]

Imp

edan

ceZ

[Ω]

Z|| < 5 kΩ• complex time domain calculationsfor a very complexgeometry

• full validation of calculations by bead-pull measurements (o)

• effective dampingalso of transverse Z

o = measured data




EU-Cavity Test @ DELTA

5/2004 – 9/20047/2005 – 8/2006




CBM Characterisation of EU-Cavity

Filling pattern:144/192 buckets filled,

Spectrum measured withEU cavity @1.5GeV

Osc

illa

tion

Am

plit

ud

e (d

egre

e)


CBM 52 not induced bycavity, also seen with theDORIS-type cavity

responsible Z|| ~ 9 kΩ

reason still unknown:

candidates:

• strip line kickers

• broken RF-contacts inbellows, valves

• resonant vacuumchambers and tapers




Summary EU-Cavity Beam Test• Successful test with beam @ 1.5 GeV (I = 140mA) and @ 542

MeV (I = 280 mA).• No cavity induced instabilities have been found.• Cavity was successful operated over more than one year in

regular user shifts.• Loss power capability of the prototype limited to 20-30 kW due to

non sufficient RF contact between HOM-dampers and body.thermal stress + micro vacuum leaks

• New HOM-damper design (BESSY) with invacuum ferrites avoiding RF-window and external HOM loads.

• ALBA (Barcelona Light Source) and the Metrology Ring (Berlin)will be equipped with EU-type cavities.

• The ESRF is planning to adept the philosophy of HOM-damping.

E. Weihreter et al., Proc. 2006 EPAC (2006) 1280R. Heine et al., Proc. 2006 EPAC (2006) 2856




O. Kopitetzki et al., Proc. 2006 EPAC (2006) 1945

• 2 independent measurements ofoptical β−functions.

• tune scan method (local variationof quadrupole strengths and orbitresponse matrix analysis (ORM).

• comparable results but at different locations

• ORM-analysis provides sensitive information on phase beating

Modelling of theMachine Optics

a big step forward towards a bettermachine modelling.




Example: Horizontal „Phase Beating“Phase Advance Deviations between Model and Measurement

modified model

refined quadrupolestrengths andmagnet locations

minimisation of ∆Ψ




Frequent Injection @ DELTA

time

bea

mcu

rren

tan

d li

fetim

e

125 mA +/ 5 %

constant lifetime

~ 7 h

G. Schmidt et al., Proc. 2004 EPAC (2004) 2299

• increased average beam current

• increased photon flux for users

• constant heat load on chambersand beam lines

• increased machine stability

• machine tests with shuttersclosed successful.

• discussions with users and approval authorities ongoing.




Acknowledgments

Financial supportfrom university, EU,

NRW, FZJ and BMBF

Help fromcolleagues from

ESRF, ALBA, SLS, Diamond.........

EU-cavity collaborationcolleagues from:

BESSY, DaresburyCLRC, MaxLab, NTHU

DELTA machineand accelerator physics

group

organisers of RuPAC

Documents

RUPAC2006 Talk Weis PPT2003 - TU Dortmund