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Review of PETRA III Diagnostics ( five years of operational experience )

Review of PETRA III Diagnostics ( five years of operational experience ). Gero Kube for the PETRA III diagnostics team DESY Hamburg. PETRA III: present status and extension project quick glance at diagnostic systems : BPMs beam losses emittance diagnostics spurious bunches

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Review of PETRA III Diagnostics ( five years of operational experience )

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  1. Review of PETRA III Diagnostics(fiveyearsof operational experience) Gero Kube forthe PETRA III diagnosticsteam DESY Hamburg • PETRA III: presentstatusandextensionproject • quick glanceatdiagnosticsystems: • BPMs beam losses • emittancediagnosticsspuriousbunches • beam current (FCTs)

  2. PETRA III @ DESY • DESY site in Hamburg • PETRA III parameters circumference:2304 m energy: 6 GeV emittance: 1 nm.rad emittance coupling : 1% current: 100 mA # bunches: 40 / 960 straight sections: 9 user beamlines: 14 undulator length: 2, 5, 10 m • PETRA history • 1979 – 1986: e+e-collider(upto 23.3 GeV / beam) • 1988 – 2007: pre-acceleratorfor HERA (p @ 40 GeV, e @12 GeV) • since 2009: dedicated 3rdgeneration light source, cost-effectivesupplementto E-XFEL DEELS 2014 Workshop @ ESRF, 12.05.2014 Gero Kube, DESY / MDI

  3. PETRA Extension • P3X motivation • DORIS III shutdown in 01/2013 • → continuationofsuccessfulexperiments @ PETRA • increasenumberofuserbeamlines • → 2 new experimental halls,10 newbeamlines DEELS 2014 Workshop @ ESRF, 12.05.2014 Gero Kube, DESY / MDI

  4. PETRA Extension • P3X • longPETRA shutdownstarted 02/2014 • constructionwork in progress • back in useroperation after about 1 year • acceleratormodifications • about 50m ofthestorage ring will bemodified on eitherside • shortdipoles, nosextupoles, spaceforundulators • concretebaseinsteadofgirders • beam diagnostics • copyandpasteofexisting P3 diagnostics • → no time fornewdevelopments DEELS 2014 Workshop @ ESRF, 12.05.2014 Gero Kube, DESY / MDI

  5. Diagnostics (P3 Design Report) • PETRA III: • 228 BPMs • → 226 forOrbit • → 227 LiberaBrilliance • 6 currentmonitors • 2 Stripline-BPMs and • 2 Button-BPMs for • Multibunch Feedback • 1 Button-BPM forlongi- • tudinal Feedback • 1 Wall Gap Monitor • 1 Laser Wire Scanner • 2 BeamlinesforEmit- • tanceDiagnostics • 3 Screens • Transfer Lines: • 20 BPMs • 10 Current Monitors • 4 Wall Gap Monitors • 11 Screens • beam losses • bunchpurity not sufficient: DEELS 2014 Workshop @ ESRF, 12.05.2014 Gero Kube, DESY / MDI

  6. BPM System Overview • BPM electronics: LiberaBrilliance • BPM pickups: 8 different pickuptypes • newoctant • P3 setup • oldoctants → softwarerelease1.87 numberincreasesfor P3X P3X: upgrade to 2.09 I. Krouptchenkov et al., Proc. DIPAC 2009, Basel, TUPD03, p. 291 DEELS 2014 Workshop @ ESRF, 12.05.2014 Gero Kube, DESY / MDI

  7. BPMs: Operational Experience (1) BPM pickups • BPMs betweencantedundulatorcellsneverused • → requirementfrom MAC • → design adapted on therushfrom APS • → strong non-linearities • unphysicalbehaviourfromsingle BPM • → verticalreading not usable • → thresholdbehaviour (singlebunchcurrent) • → BPM switched off fromorbitcontrol quasi ellipticalshape: 57x7 mm buttondistance: 9.652 mm buttondiameter3.9878 mm HOMs ??? DEELS 2014 Workshop @ ESRF, 12.05.2014 Gero Kube, DESY / MDI

  8. BPMs: Operational Experience (2) BPM electronics • in principleLiberaBrillianceworksfine, but requiressomework-arounds • digital signalconditioning (DSC) algorithm • → switchingartefacts in TbTdata • → sometimesblocked DSC coefficients • → learningduring strong signallevelchangesmaycorruptcoefficients F. Schmidt-Föhre et al., Proc. DIPAC 2011, Hamburg, TUPD21, p. 350 work-around: from time totime DSC auto-learning DEELS 2014 Workshop @ ESRF, 12.05.2014 Gero Kube, DESY / MDI

  9. BPMs: Operational Experience (3) BPM electronics (cont.) • fast lifetimemeasurement via BPM sumsignal • → several BPMs showunstablesumsignal • → ESRF: temperatureandpositioninfluence • → unstable DSC I-Tech: “Angel confirmed that the DSC now works OK at Alba.” • failureof 12 V supply power • → about 10 times in 5 years, reason not yetunderstood (andinvestigated) • pile-upfromtasksystem • → uselesscronjob, compromisingtheperformance (work-around: scanning all Liberas, removingbyhand) • → problemseemstobesolvedbysoftwareupdates P3X: improved DSC algorithmwith 2.09 upgrade DEELS 2014 Workshop @ ESRF, 12.05.2014 Gero Kube, DESY / MDI

  10. X-rayoptics X-ray optics CCD Monochromator Si (311) Monochromator Si (311) CCD EmittanceDiagnostics imagingwithCompoundRefractive Lens (CRL) optics: X-raybeamline • design photonenergy • → ħω = 20 keV • verticalresolutionbroadening • → design emittance: εv = 10 pm.rad DEELS 2014 Workshop @ ESRF, 12.05.2014 Gero Kube, DESY / MDI

  11. EmittanceDiagnostics (2) setup improvements • exchangeofmonochromatorcrystal • improved CRL mounting • improveddetectorsetup • → measuredverticalemittancenearly • unaffected assumption • photonenergyslightlybelow 20 keV • → indicationfromtestmeasurementbeforeshut-down machine studies: Ultimate Storage Ring • natural beam emittance reductionof beam energy: 3 GeV(insteadof6 GeV) → emittancereductionbyfactor4 → dampingwigglercontribution: εh = 158 pm.rad • SR criticalenergy → SR spectrumbyfactor8→ ħωc = 2.6 keV X-raybeamline: 20 keV opticalmethod DEELS 2014 Workshop @ ESRF, 12.05.2014 Gero Kube, DESY / MDI

  12. SR-Interferometer @ PETRA setupin opticalhutch opticalbeamline (bunchlengthdiagnostics) Glan-Thomson polariser Ü magnificationlens visible light beampipe mirror boxes lens double slit bandpassfilter & CCD synchrotron light from bending magnet NL 50 alignmentmirror • 30 m beam transport via relayopticalsystem vertical design emittanceconfirmed DEELS 2014 Workshop @ ESRF, 12.05.2014 Gero Kube, DESY / MDI

  13. SR-Interferometer @ PETRA drawbacks USR studies • confirmationof 3 GeVhor. emittance • beamlinewithrelayoptics • → additional uncertainties (lenses) • setupblocksStreakcamerasystem • → dismountinterferometerforbunch • lengthmeasurement • spaceforonlyoneinterferometer • → modifysetupformeasurement in • othertransverse plane new optical beamline for P3X • constructionwork in progress • → status 6.5.2014 beamline originally not designed for interferometric measurements DEELS 2014 Workshop @ ESRF, 12.05.2014 Gero Kube, DESY / MDI

  14. In-Flange Fast Current Transformers 3 In-Flange FCTs installed in PETRA 1st damaged after longer operation with 40 bunches @ 1011 particles (80 mA) 2nd damaged after 40 bunch operation in 90 mA 1.5 years later • installationof (provisional) aircooling investigation from Bergoz: black residue on flanges inner surface (material seems to be cyanoacrylate impregnatingthemagneticcores) outer core wrapping: polyester tape burnt inner core wrapping: fiberglass tape blackened epoxy holding the core in the flanges browned and retracted 50Ω load: one resistor blown one end of the 20‐turn winding desoldered 20‐turn winding inductance 150μH (instead of 4.5mH initially) → relative permeability dropped from about 120000 to 4000 assumption: temperatures of much more than 100°C inside the monitor due to transient losses DEELS 2014 Workshop @ ESRF, 12.05.2014 Gero Kube, DESY / MDI

  15. In-Flange FCTs thermal simulations with CST courtesy: D. Lipka (DESY/MDI) • high thermal losses in 40 bunchmode • → transient effects • dominant mode • → leakingthrough FCT gap • → power deposition in thermally • isolatedcore • temperaturesbetween 100°C and 200°C possible • → depending on thermal coupling https://www.cst.com/Applications/Article/Heat-Load-Investigation-Of-A-PETRA-III-Toroid monitor improvements (Bergoz) • replacementofmagnetcore • → material withhigher Curie temperature • betteraircoolingofmagnetcore • installationoftemperaturesensor • → temperatureatmagnetcore • mechanicalmodifications • → betteraircirculation newmonitorsinstalledfor P3X DEELS 2014 Workshop @ ESRF, 12.05.2014 Gero Kube, DESY / MDI

  16. Beam Loss Monitoring BLM system originally not planned for PETRA operation in time resolved (40 bunch) mode • Touschek limited lifetime • → τ ≈ 1.4 h top-up operation • observationofradiationdamage • → rustatundulatormagnets • → undulatorperformancedegradation • → damagedcables installation of HERA BLM system close to IDs • monitor → 2PIN-photodiodes mounted face-to-face coincidence counting: insensitive to synchrotron radiation → up to 10 MHz count rate → dynamic range > 1E8 → 13 years successful operation at HERA DEELS 2014 Workshop @ ESRF, 12.05.2014 Gero Kube, DESY / MDI

  17. BLM Experience injected beam losses BLM1 BLM2 circulating beam losses DC current BLM rate reduced Touschek contribution life time DEELS 2014 Workshop @ ESRF, 12.05.2014 Gero Kube, DESY / MDI

  18. Loss Contribution observation of beam losses from • injected beam • circulating beam BLM system • countingoflosses • noinformationaboutenergydeposition Cherenkov (scintillator) fiber based BLMs • testinstallationat 2 IDs • studieswith beam • → onlyinjection beam losses • installationof 1mm thickscintillatingfiber BLM system with sensitivity on deposited energy observation of losses only from injected beam dominant loss contribution ??? studiescontinue after P3X commissioning DEELS 2014 Workshop @ ESRF, 12.05.2014 Gero Kube, DESY / MDI

  19. Spurious Bunches trouble-free operation until mid of 2012 suddenly user complaints • time resolvedmode (40 bunchesoperation) • → nuclearforwardscatteringexperimentswithsynchrotronradiation (i.e. Mössbauer in time domain) • observationof 16 ns time structure in NFS temporal beatpattern courtesy: H.-Ch. Wille (DESY) 2 h sample time, sp. bunch rate < 5 Hz, regularwith 16ns distance prompt at t = 0 nsmeasuredonlyforfractionof a second detector noise < 0.1 Hz spuriousbunchesat 8 nswith 10-7intensity APD noiseupto 20ns ? clean from 20 nsup DEELS 2014 Workshop @ ESRF, 12.05.2014 Gero Kube, DESY / MDI

  20. Spurious Bunches decision to build user independent spurious bunch monitor X-rayAvalanchePhoto Diode • freeportbehindmonochromatorof X-raydiagnosticbeamline • → dirtysurrounding in tunnel • → background due to X-rayfluorescence APD detector monochromatorchamber γ diffuse scatterer monitor extensively used for studies • spuriousbunches due totimingissues in injectorchain • → usersare happy withpresentsituation • monitorsuffersfromdirtysurrounding • → so faronly qualitative measurementsofbunchpuritylevel optimization still ongoing DEELS 2014 Workshop @ ESRF, 12.05.2014 Gero Kube, DESY / MDI

  21. Summary and Outlook • statusofPETRA III and PETRA III extensionproject • operationof PETRA III diagnostics in generalstableandreliable • forsometaskswork-aroundsrequired • diagnosticsasplanned in PETRA design report was not sufficient • commissioningof P3X with additional andimproveddiagnosticsiswaiting • somefaultydevices • → FCTs • → BPMs (pickupandLiberas) • Libera DSC coefficients • opticaldiagnosticsbeamline • spuriousbunches • BLMs → hottopic: degradationof IDs many thanks …. • to all colleaguesfromthe P3 diagnosticsteam • especiallytoM.Bieler, R.Neumann, D. Nölle, D.Lipka, F.Schmidt-Föhre, H.-Ch. Wille, K.Wittenburg(DESY) • J.BergozandF.Stulle (Bergoz Instrumentation) • andfinallyspecialthankstoKees Scheidt, Philippa Gagetfororganizingtheworkshop DEELS 2014 Workshop @ ESRF, 12.05.2014 Gero Kube, DESY / MDI

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