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Matching PSB-PSMatching PSB-PSM.Benedikt, A.Jansson, M.Giovanozzi, M.Benedikt, A.Jansson, M.Giovanozzi,

M.Martini, PSB teamM.Martini, PSB team

New better dispersion matched optics New better dispersion matched optics tested tested

Theory and experiment agree to first order (emittance?)

Conceptual design for betatron matching of Conceptual design for betatron matching of the four PSB rings with a single quadrupole the four PSB rings with a single quadrupole on ring 1 and 2 on ring 1 and 2

Draft note ready Design for quadrupole complete

Very encouraging first results from Very encouraging first results from prototype quadrupolar pick-up in the PSprototype quadrupolar pick-up in the PS

Design of final pick-up started Dedicated matching MD needed

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Qudrupolar pick-upQudrupolar pick-up

0.1 0.2 0.3 0.4 0.5Fractional FrequencyHqL

20

40

60

80

ed

ut

il

pm

AHmm2 L

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PSB SynchronizationPSB SynchronizationA.Blas, PSB teamA.Blas, PSB team

Longitudinal bunch jitter suppressedLongitudinal bunch jitter suppressed Synchronization fasterSynchronization faster

H=1 H=2

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High intensity in PSBHigh intensity in PSBM.Chanel, E.Jensen, G.Cyvoct, PSB teamM.Chanel, E.Jensen, G.Cyvoct, PSB team

E (GeV) h USER RING Intensity(10^10)

1.4 D/1 MEPSB All 3600

1.0 D/1 ISOGPS All 3700

1.4 D/2 MEPSB All 3600

1.4 D/1 MDLHC 2 1000

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1.4 GeV for ISOLDE1.4 GeV for ISOLDEG.Cyvoct, M.Lindroos, PSB teamG.Cyvoct, M.Lindroos, PSB team

Test beam 1999Test beam 1999 Maximum intensity 2500 10^10Maximum intensity 2500 10^10 To reach the nominal 3000 10^10 particles To reach the nominal 3000 10^10 particles

per pulse the transfer between the PSB and per pulse the transfer between the PSB and ISOLDE has to be re-optimizedISOLDE has to be re-optimized

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InstrumentationInstrumentation

BeamScope available for emittance BeamScope available for emittance measurements!measurements!

Needs more time after synchronization Needs more time after synchronization (before ejection) for good measurements(before ejection) for good measurements

Possible with new synchro modules

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Hollow bunchesHollow bunchesA. Blas, S. Hancock, S. Koscielniak, M. Lindroos, F. Pedersen, A. Blas, S. Hancock, S. Koscielniak, M. Lindroos, F. Pedersen,

H. Schonauer, M.Sjöström, PSB TeamH. Schonauer, M.Sjöström, PSB Team

Why: Why: to improve space charge related to improve space charge related problems.problems.

How: How: Increase the IIncrease the Imean mean / I/ Ipeakpeak= BF value by = BF value by creating a hollow distribution in the creating a hollow distribution in the longitudinal phase spacelongitudinal phase space

Objective July 99:Objective July 99: Reproducible and stable Reproducible and stable flat LHC type bunchflat LHC type bunch

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Hollow bunches (history)Hollow bunches (history)

F. Pedersen (PSB 1978): F. Pedersen (PSB 1978): h = 5 bucket deposit in a 50 MeV coasting h = 5 bucket deposit in a 50 MeV coasting beam and acceleration with h = 5 and 7.10beam and acceleration with h = 5 and 7.101010 p (no fast FB!) . p (no fast FB!) .

K. Schindl (PSB 1978): K. Schindl (PSB 1978): Use of dual harmonic debuncher in the Use of dual harmonic debuncher in the Linac transfer lineLinac transfer line

ResultsResults: : loss of hollowness when closing any loop. Abandoned because loss of hollowness when closing any loop. Abandoned because of the success of dual harmonic (h5 + h10) operation.of the success of dual harmonic (h5 + h10) operation.

R. Garoby, S. Hancock (PS 1992): R. Garoby, S. Hancock (PS 1992): Phase shaking at ~ 0.94 fPhase shaking at ~ 0.94 fSS and and homogenization with 200 MHz cavity. Very successful from 1GeV homogenization with 200 MHz cavity. Very successful from 1GeV to 26 GeV trough transition.to 26 GeV trough transition.

S. Hancock (PSB 1997): S. Hancock (PSB 1997): same method as above, but h=16 same method as above, but h=16 frequency control too poor at that time to get proper results.frequency control too poor at that time to get proper results.

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Bucket depositionBucket deposition

Computer simulation of longitudinal phase space after deposition of V16=1kV empty buckets; T=5ms

04/19/23 M.L. 10

Bucket deposition (rf set-up)Bucket deposition (rf set-up)

An “empty” bucket is An “empty” bucket is brought into the brought into the injected beam before injected beam before capturecapture C16 cavity for “hole-

generation” C02 cavity for

acceleration (h=1)

C16 frequency

Sweep time

40 kHz

C16

C02

injection

Time (s)

Voltage (kV)

310 315 320 325 330 335

4

8

Time (s)

Frequency (kHz)

310 315 320 325 330

Frequency of the “synchronous” particle

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Beam transfer functionsBeam transfer functions

H()

G()

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TomogramsTomograms

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LHC type beam in PSLHC type beam in PS

•No transverse blow-up due to bunch flattening process

•Reproducible

•10-15% gain in bunching factor

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Status of flat bunchesStatus of flat bunches

““Flat” LHC type beam producedFlat” LHC type beam produced reproducible transferable PSB->PSB

Instability of “hollow bunches” understoodInstability of “hollow bunches” understood Still to do:Still to do:

High intensity flat single harmonic bunches Dual harmonic flat bunches?