Status of DAFNE: from KLOE-2 to SIDDHARTA-2 experiment …eefact2018.ust.hk/files/20180924/20180924-1425-Catia Milardi.pdf · A REVIEW OF DAFNE PERFORMANCES DURING THE KLOE-2 RUN

eeFACT18 – 24÷27 Spt 2018 – Hong Kong

CatiaMilardionbehalfoftheDAFNETeam

StatusofDAFNE:fromKLOE-2toSIDDHARTA-2experimentwithCrab-Waist

A REVIEW OF DAFNE PERFORMANCES DURING THE KLOE-2 RUN Catia MilardiIPAC’18 – May 2018 - Vancouver

Outline

• DAFNEoverview

• KLOE-2operations

• Beamphysicsstudies

• SIDDHARTA-2preparatoryphase

• DAFNEtimeline

• Conclusions

DAFNE status: from KLOE-2 to SIDDHARTA-2Catia MilardieeFACT18 – 24÷27 Spt 2018 – Hong Kong

BTF

X-ray 900 - 3000 eV

IR 1.24 meV - 1.24 eV

UV 2 - 10 eV

TheDAFNEAcceleratorComplex

LNFarealsopartoftheEuropeansynchrotronlightInfrastructures

e+ e-

C ≈ 97 mECM = 1.02 GeV (F)

FrascatiNationalLaboratories(LNF)


DAFNEnative

DAFNE Crab-Waist

Energy (MeV) 510 510qcross/2 (mrad) 12.5 25ex (mm•mrad) 0.34 0.28

bx* (cm) 160 23sx* (mm) 0.70 0.25FPiwinski 0.6 1.5by* (cm) 1.80 0.85

sy* (µm) low current 5.4 3.1

Coupling, % 0.5 0.5

Bunch spacing (ns) 2.7 2.7

Ibunch (mA) 13 13sz (mm) 25 15

Nh 120 120

DAFNELayoutandParameters

FINUDA (DEAR)

KLOE

“Proposal for a F-factory”, LNF-90/031 (IR),1990.

CollidingBeamshave:lowEhighcurrentsshortbunchspacing2.7nseclongdampingtime

native

DAFNE Crab-Waist


ConventionalApproachtoHighLuminosity

𝐿 = 𝑁$𝑓&'(

)*+,∗+.∗𝐿 = 𝑁$𝑓&

*/(0,0.1,23(4.∗

1 + +.∗

+,∗7

𝜉9,; =𝑁𝑟=2𝜋𝛾

𝛽9,;∗

𝜎9,;∗ 𝜎9∗ + 𝜎;∗

Small 𝜷𝒚∗

Highernumberofparticleperbunch𝑵

Morebunches𝑵𝒃

Highertuneshift𝝃𝒙,𝒚

Greaterhorizontalrmsbeamsize𝝈𝒙Smallcrossingangle𝜽𝒙

SmallPiwinskyangle𝜱 = 𝝈𝒛𝝈𝒙𝐭𝐚𝐧 𝜽𝒙

𝟐< 𝟏


z

Overlap area @ IP

sz

by*

y

ConventionalApproachMeetsLimitations𝜷𝒚∗ ~ 𝝈𝒛 toavoidhourglasseffect

𝝈𝒛 reductionledto:singlebunchinstabilitybunchlenghteningandmicrowaveinstabilityiesCSRproduction

Higher𝑵 and𝑵𝒃ledtoenhancedpowerlossesincreasewallplugpowerrequirementscausescoupledbunchinstabilityies

Tuneshifts𝝃𝒙,𝒚 arerestrictedbythebeam-beamlimit

Larger𝝈𝒙 conflictswithbeamstayclearanddynamicalaperturerequirements

Long-rangebeam-beaminteractionscausingt+ t-

reductionlimitingI+MAXI-MAX and->Lpeak andL∫


Crab-Waist CollisionScheme


Horizontalcrossingangleq

LargePiwinskiangleF

LargePiwinskiangle

New IR layoutLower beam e

large qsmallsx

• low zx,y (tune shift)• Lgeometric gain

𝜷𝒚∗ canbereducedforsakeofthebeamsoverlapregionS

• Lgeometric gain• lower zy• synchro-betatron resonances suppression•zy reduction with the synchrotron oscillation amplitude

New low-b sectionAd hoc low-b optics

P. Raimondi et al., LNF-07/003 (IR) 29 Gennaio 2007


Collisionswithlargeq isnotanewidea

Crab-Waist transformationis

LargePiwinskiangle

P. Raimondi , 2° SuperB Workshop, March 2006,P.Raimondi, D.Shatilov, M.Zobov, physics/0702033,C. Milardi et al., Int.J.Mod.Phys.A24, 2009.

Powerful SextupolesProper IR optics

sextupole (anti)sextupole

IP

• Lgeometric gain• X-Y synchro-betatron and betatron resonance suppression

withoutCWSextupoles


Collisionswithlargeq isnotanewidea

Crab-Waist transformationitis

LargePiwinskiangle


Powerful SextupolesProper IR optics

sextupole (anti)sextupole

IP

• Lgeometric gain• X-Y and synchro-betatron resonances suppression

withCWSextupoles


KLOE-2IR

10m

C. Milardi et al 2012 JINST 7 T03002.


native

DAFNEandKLOE-2

ECM = 1020 MeV

Crab-Waist collision scheme implemented for the first time with a large detector including a strong solenoidal field


DAFNEActivityProgramforKLOE-2

PreliminaryTestPhase fall2010÷ Dec2012

ColliderConsolidationKLOE-2detectorlayersinstalled Dec2012÷ Jun2013

KLOE-2datataking

IRun Nov16th 2014÷ Jul3rd 2015goal1fb-1

IIRun Spt 28th 2015÷ Jun29th 2016goal1.5fb-1

IIIRunSpt 12nd 2016÷ Aug1st 2017goal2fb-1

IVRunSpt 6th 2017÷Mar31st 2018goal1.5fb-1


IRun

IIRun

IIIRun

IVRun

KLOE-2RunOverview

! " #$%&'$($#�

*+,≈ 68043456

! " 789:&($#�

*+,≈ 54893456


MonthbyMonthLuminosityTrend∫ Ldel (pb-1)∫ Lacq (pb-1)


BestOperationsMonth∫ Ldel (pb-1)∫ Lacq (pb-1)


HighestHourlyIntegratedLuminosity

∫1h L~0.67pb-1

Nb =107

∫1day L~16pb-1


∫ Ldel ~14.3pb-1∫ Lacq ~11.9pb-1Uptime~98%

HighestDailyIntegratedLuminosity

• 106bunches• Sustainablebackground

29/Jan/2018 ÷ 4/Feb/2018

∫ Ldel ~ 86.6 pb-1


Crab-WaistLuminosityGainCrab-Waistprovidesa59%increaseintermsofpeakluminosityasevidenceded bydatatakenbythesamedetectorwiththesameaccuracy


Crab-WaistLuminosityGain

120*Amp2 /Nbunch

lum

inos

ity/1

e28

24/11/14 KLOE-228/01/18 KLOE-2

16/09/2005 Kloe best06/08/2002 Kloe best

5000

10000

15000

20000

25000

0 0.5 1 1.5 2 2.5

Lum

inos

ity [1

028

cm-2

s-1 ]

Crab-Waist collision scheme:y ~ 1.5 b*y = 8.5 [mm]KLOE-2 24/Nov/2014KLOE-2 28/Jan/2018

ORIGINAL COLLISION SCHEME:KLOE 2005 y ~ 0.6 b*y = 18. [mm]KLOE 2002 y ~ 0.3 b*y = 25. [mm]

!"!#$%&'()*+,$-.*,%/0 23


DAFNE CW upgradetested with SIDDHARTA (2009)

DAFNEKLOE (2005)

DAFNE (CW)KLOE-2 (2014)

Lpeak [cm-2s-1] 4.53•1032 1.50•1032 2.38•1032

I- [A] 1.52 1.4 1.18I+ [A] 1.0 1.2 0.87Nbunches 105 111 106∫dayL [pb-1] 14.98 9.8 (seldom) 14.3

Lpeak exceedsbya59%thebestluminosityeverachieved,atDAFNE,duringoperationsforanexperimentalapparatusincludinghighfielddetectorsolenoid.

PeakLuminosity


MachineStudies


10BunchesCollisionsAiming at minimizing the impact of multi-buncheffects and e-cloud instabilities on Luminosity

• Lpeak~3•1032 cm-2 s-1 mightbeachievedbycolliding100bunches

• Beam-beamisnotalimitingfactor• Crab-WaistSextupoleswork


BackgroundControl

Thenewdetectorlayersinstalledaroundthebeampipeposednewtightrequirementsonbackgroundlevelandcontrol.

Criteriaforacceptablebackgroundbecame:• countingrateonthedetectorendcaps• currentamplitudemeasuredbythedifferent

driftchambersectors• dischargethresholdontheinnermostITlayer

BackgroundontheITwasheavilydependentontheinjectionprocesswhichhadtobeaccuratelyoptimizedandstabilizedEvensmalldriftsintheenergyoftheincomingbeam,0.01 ÷ 0.02 %, werecausingunaffordablebackgroundlevel.


Numerical simulations aiming atimproving:

dynamical aperturespecific luminosity

led to define a new working pointfor the e- ring

Qx=0.135 Qy=0.17

e- RingWorkingPointScan

FMAQx=0.088Qy=0.152

FMAQx=0.130Qy=0.170

M. Zobov et al., IEEE Trans. Nucl. Sci., Vol. 63, no. 2, pp. 818-822,2016.

achieving:larger DA 2 – 3 sImproved injection efficiencyhigher beam lifetimereduced background ~ 20%higher luminosity ~ 7%


ElectronBeamDynamics

DuringtheKLOE-2runthemaximume- currentsstoredatregimeincollisionhasbeenintherange

1.3÷ 1.5AItwasmainlylimitedby:

ionintheresidualgasimpedanceinducedeffects(TMCI)

Ionsareneutralizedintroducingasuitablegapinthebatch

Asdynamicalvacuumwasimprovingfilledbuncheshavebeenprogressivelyincreasedtherangeof93÷ 108 withthesametotalcurrent,thusreducing:

Touschekcontributiontothebackgroundtheimpactofthemicrowaveinstabilitythreshold

Bestmachineperformanceshavebeenachievedthroughcollisionsof106consecutivebunches.


PositronBeamDynamics

DuringtheKLOE-2runthemaximumcurrentstoredinthee+ beamhasbeenoftheorderofI+ ~1.2A.

Higheste+ currentstoredroutinelyincollisionrarelyexceededI+ >0.95avalueconsiderablylowerthantheoneachievedduringthepastruns

Beamdynamicsinthee+ ringisclearlydominatedbythee-cloudinducedinstabilities

AtDAFNEthee-cloudeffectsarecontrolledby:solenoidwindingsFBKsystemselectrodesECEmovingxx xy tohigherpositivevalueslengtheningthebunchbyreducingtheRFcavityvoltage


ECEhavebeenfundamentalinordertoachievehighe+ currentsmostlyinthefirststageofoperations

Attheendoftherunonly2outofthe12deviceswereworkingproperly,noneofthemwasinthewigglers

Highcurrentoperationshavestillbeenpossiblethankstothescrubbingprocessasconfirmedbythedataabout

vacuumpressureriseinthee+ringarcstunespreadmeasurements

AposteriorianalysistoexplaintheECEbehavioueisunderway

ExperiencewithECEatDAFNE

2 ECE3 ECE

VUGPS203

2 ECE920 mA 28/3/2018

Dnx along the batch

• All ECE off• All ECE on 2014

Dnx along the batch


InalowenergymachineasDAFNEhighcurrentperformancesdependgreatlyonbunchbybunchfeedbacksystems.

DAFNEworksroutinelythankstothe3bunchbybunchfeedbacksinstalledineachring

Thetotalpoweravailableforeachapparatusisoftheorderof500Wand750Wfortransverseandlongitudinalfeedbacksrespectively

Beamcurrentlimitsobserved• longitudinalmode-0&quadrupoleoscillations• noisecomingfrompickups(harmfulforverticalsizes)• e-cloudeffects(inthee+ring)

Solutions:• Longitudinalquadrupolecontrolbyaspecialtechnique

implementedatDAFNEinthedipolefeedbacksystem• Transverselownoisefrontend(incollaborationwithKEK)

DAFNEFeedbackSystems


Revolution harmonic Synchrotron (dipole) oscillations damped by Long FBK

(A.Drago, et al., PRST-AB, 6, 052801-1-11, 2003)

The present source of quadrupoleinstability is still under investigationThis instability, if not controlled, saturates the longitudinal feedback

@ f ~ 2 • fsync

LongitudinalQuadrupoleOscillations

Quadrupole oscillation


TimeManagmentAchievingmilestonesfortheKLOE-2runrequiredacarefulschedulingofthetimefor:

maintenancemachinestudiesandmeasurementsfacingunexpectedfaultsevencausedbyexternalfactorsdatataking

lookingatthemachineuptime,attheintegratedluminositytrend,andatthefaultrateineveryacceleratorsubsystems

Regardlessthemajorupgradeplannedbeforethestartoftherun,manyrelevantmeasureshadtobedoneduringdatatakingasforinstance:

replacementoftheCryoplantcompressorrevisionofthecoolingsystemservinglow-b sectionanddetectorelectronicequipmentrevisionofthewigglermagnetcoolingsystem

Timeoriginallyallocatedformachinestudiesandmeasurementshasbeenoftenspentfor:planninginterventionssuggestedbyanomalousfaultratesinspecificsubsystemsoutliningproblemsresultinginsubtleeffectsaffectingbeamopticsandbeamdynamics.

Asinthecaseoftheelectronicphaseshifterine- ringLLRFwhichcausedtheRFphase,andconsequentlythebeam,toshiftslowlyandrandomlybyabout10deg

ThisapproachandaconsiderablelackofmanpowerdidnotallowtoexploittheDAFNE’sfullpotentialasacollider,butassureddatataking.


DAΦNETimeline

March31st 2018endoftheKLOE-2Run

April÷ JulyKLOE-2roll-out(completedonMay28th)

January2019SIDDHARTA-2IRinstallation

Inyear2019SIDDHARTA-2datataking

Startingfrom2020DAFNEmightbetransformedinatestfacility:

DAFNE-TF


SIDDHARTA-2PreparatoryPhase


https://www.youtube.com/watch?v=ThDEwuhE1hA

KLOE-2leavesthestage


SIDDHARTA-2low-b section

PMQF

PMQD

• large collision angle ~ 50 mrd• low-beta section based on

Permanent Magnet QUADs:KQD = -29.2 [T/m]KQF = 12.6 [T/m]

• four C type Corrector dipole are used to mach the vacuum chamber in the arc

IP

ItisessentiallybasedonthesamedesignconceptsusedfortheSIDDHARTAone

PMQD

PMQF

PMQF

PMQFNewvacuumchamberAddidionaldiagnosticsThepermanentmagnetquadrupoles,thathavebeenrebuiltaimingat:

• speedinguptheinstallationprocedure• improvingdesignissuessuchas:

v goodfieldregionv gradientuniformityv mechanicalassembly forPMQFv apertureforPMQDaiming atimproving:

stayclearaperturebackgroundluminositymonitorefficiency


PMQD PMQF

BeamPipeApertureH-V(mm)at IP (I row) and at Y (II row) side

5769- 55

54

InnerApert.WithCaseH-V(mm) 72- 62 58OuterDiameterH-V(mm) 238- 220 95.6Mech.LengthInner-Outer(mm) 220 168- 240NominalGradient(T/m) 29.2 12.6IntegratedGradient(T) 6.7 3.0GoodFieldRegion(mm) ±20 ±20IntegratedFieldQuality|dB/B| 5.00E-4 5.00E-4MagnetAssembly 2halves 2halves

NewPMQsareHalbachtypemagnetsmadeofSmCo2:17PMQs havebeendesignedincollaborationwiththeESRFmagnetgroup.

PMQsspecifications

58-QF Aperture

PMQF

PMQD


IRVacuumChamberThePMQDvacuumchamberhastapereddesigninordertomatchthePMQDsaperturewiththecircularcrosssectionoftheIPbeampipe.IthasbeenengineeredwithspecialattentiontotheHOMtrappedintheYshapedchamber.

Topview


AdditionalHorizontalFBKine+ RingThemaximumcurrentstoredinthee+ beamislimitedbythee-cloud inducedeffects.Twoe-cloudelectrodes (ECE)onlyworkproperlythefaultyoneswillnotbereplaced.NewAlvacuumchamberintheIR.AnadditionalhorizontalfeedbacksystemwillbeinstalledinthepositionpreviouslyoccupiedbytheDampKicker

additional feedback system


LuminosityMeasurements

SmallAngleCrystalCALorimeters withTimeMeasurementCCALT:

• measuresBHABA scatteringeventatsmallangle• providesabsoluteinstantaneousluminositymeasurementeveninbunchbybunchmode

• accuracy5÷10%dependingonrepetitionrateandthresholdsettings

• ithasbeentestedduringtheKLOE-2run

Gammabremsstrahlungproportionalcounterhavinghighrate,butlowprecision;itwillbeusedtoestimateluminosityrelativevariations

KaonmonitorwhichispartoftheSIDDHARTA-2apparatus

ComparisonbetweentheLuminometersignalrate(red)andthereferenceluminositymeasuredbyKLOE-2(blue).


OtherPreparatoryPhaseActivitiesPowerSupplies

Allthe~500PSmaintainedpulsedmagnetPSsupgradedbyreplacingcapacitorbankssteeringmagnetPShopefullyreplacedinbothrings

PowerSuppliesAllthecorrectorspowersupplies(shortandlong)bothinthepositronsandintheelectronsringswillbereplacedwithnewdeviceshavingafactor10improvedaccuracyandresolution.

DampKickersTheoneinthee- ringwillbereplacedbyastraightsectionInthee+ ringitwillbereplacedbyanewhorizontalfeedbackkicker

VacuumexhaustedvacuumpumpsreplacedNEG intheIRreplaced

CoolingSystemVariableSpeedDrivewillbeinstalledupstream:

thecoolingtowerservingAandTLsthecircuitservingthemainringsmagnets


SIDDHARTA-2PreparatoryPhase

ControlSystemConsolesrunningtheGUIwillbereplacedwithupgradeddevices

Machine– ExperimentDataExchangedesignofthenetworkdedicatedto:

- acquisitionandmanagementoftheexperimentfront-end;

- dataexchange betweenthecolliderControlSystemandtheexperimentdataacquisition.

definitionof:- variablesetandrelatedformat;- dataexchangeprotocols(JSONstreamingthroughhttpRESTandNFS).


Conclusions

DAFNEhasjustconcludedtherunfortheKLOE-2experimentachievingunprecedentedresultsintermsofluminosity.

ThishasbeenpossiblethankstoaneffectiveintegrationoftheCrab-WaistCollisionSchemewiththehighfielddetectorsolenoid.

TheCrab-WaistCollisionSchemehasproventobeaviableapproachtoincreaseluminosityincircularcolliderseveninpresenceofanexperimentalapparatusstronglyperturbingbeamdynamics.

GoodnewsforallthenewmachinesandprojectsaroundtheworldthathaveadoptedCrab-Waistastheirmaindesignconcept.

ThepreparatoryphasefortheSIDDHARTA-2runiswellestablished


Thankyouforyourattention




Status of DAFNE: from KLOE-2 to SIDDHARTA-2 experiment …eefact2018.ust.hk/files/20180924/20180924-1425-Catia Milardi.pdf · A REVIEW OF DAFNE PERFORMANCES DURING THE KLOE-2 RUN

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