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Towards electron spectroscopy on a FAST ion beam at FLASH

Marko Förstel Max-Planck-Institut für Plasmaphysik / für Kernphysik AG Hergenhahn : U. Hergenhahn , M. Mucke, T. Arion , T. Lischke , H.-P. Rust, A. Bradshaw. Towards electron spectroscopy on a FAST ion beam at FLASH. Introduction. Overview of talk The TIFF facility at FLASH

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Towards electron spectroscopy on a FAST ion beam at FLASH

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  1. Marko Förstel Max-Planck-Institut für Plasmaphysik / für Kernphysik AG Hergenhahn: U. Hergenhahn, M. Mucke, T. Arion, T. Lischke, H.-P. Rust, A. Bradshaw Towards electron spectroscopy on a FAST ion beam at FLASH

  2. Introduction • Overviewof talk • The TIFF facilityat FLASH • Ion fragmentspectroscopy • Extension ofTIFF and firstexperimentsat FLASH • addelectronspectroscopy • Experimentsandtestsat BESSY (introducingtwo) • New experimentsandtestsat TIFF • Plannedexperimentsat FLASH Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010

  3. TIFF at FLASH TIFF at FLASH Massselectedtargets Fragment spectroscopy Wide rangeofspecieswhichareotherwise not accessible Fast beam -> neutral detection Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010 05.02.2014

  4. Extension of TIFF at FLASH with an electronspectrometer TIFF at FLASH TIFF Jr. and ESPEC FLASH beam addelectronspectroscopytoexistingsetup Switchingofion beam allows twoexperiments on the same target Ion beam Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010 05.02.2014

  5. Extension of TIFF with an electronspectrometer 05.02.2014 • Alignmentandcomissioningofnewsetup in Hamburg • Achievedtransmissionofionsthrough TIFF jr. ofabout 80 % • Pressure in interactionchamberatabout < 2*10-10mBars (using MPIK bakeoutcomputer) Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010

  6. The electronspectrometer 05.02.2014 Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010

  7. The electronspectrometer ion beam ) drifttube FLASH todetector aperture electrontrajectories magnettip magenticfieldlinesperpendiculartodrawnlines Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010 05.02.2014

  8. First experimentsat FLASH Parameters for FLASH experiment Assuming: Integrated photonflux = 1.03 *1014 /s Size interactionregion = 0.43 cm3 05.02.2014 Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010

  9. First experimentsat FLASH hv = 92 eV Ne+ -> Ne2+ Black line = ion beam off Redline = ion beam on counts / arb. u. green - difference t.o.f. / channel # Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010

  10. First experimentsat FLASH Neon+ionization • Count rate 1 Hz • (47 expected) • First threedoublyionizedstatesareseen Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010

  11. First experimentsat FLASH - conclusions Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010 • Fragment spectroscopysuccessfull (TIFF IZ) • Feasibility in principleshown • Considerableimprovementsneeded • Beam overlapandalignmentprocedure • Mag. bottleenergyresolution • Vacuumimprovements

  12. Experiments andtestsat BESSY – a newspectrometer coil outside thevacuum… d = 76 m smallermagnettip… Time structure:‚Single bunch‘ (one e- packet, 800 nsgap) 05.02.2014 Makenewbottleandcharacterizeitat BESSY… Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010

  13. Tests andexperimentsat BESSY – argon band structure • betweenatom (monomer) andbulk • how do physicalpropertieschangewithsize? • (meltingpoint / structure…) • clusterspecificproperties? • whatsizemakes a cluster „bulk“ like? 05.02.2014 Clusters Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010

  14. Tests andexperimentsat BESSY – argon band structure Supersonicjet expansionchamber reaction chamber nozzle transversally cold,directed jet skimmer direction of gas flow parameters: stagnationpressure ~ somebars nozzletemperature ~ 40-300 Kp (exp. chamber) ~ 10-3mbar p (reactionchamber) ~ 10-6mbar 05.02.2014 Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010

  15. Tests andexperimentsat BESSY – argon band structure Argon 3p Monomer Monomer Excitationenergy = 17.1 eV 3p3/2 3p1/2 Normalizedintensity / arb. u. Binding energy / eV Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010

  16. Tests andexperimentsat BESSY – argon band structure Argon Cluster (<N> = 191) Cluster + Monomer Excitationenergy = 17.1 eV Normalizedintensity / arb. u. Binding energy / eV Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010

  17. Tests andexperimentsat BESSY – argon band structure Argon Cluster dE = 0.7eV Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010

  18. Tests andexperimentsat BESSY – argon band structure Argon Cluster (<N> = 1700) using a hemisphericalanalyzer Redlineseenby Feulner et al.(unpublishedresults) on monocrystallineargon Also visible on polycrystallinelayers: Schwentner et al. Phys. Rev. Lett. 34, 538 (1975) 05.02.2014 Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010

  19. Tests andexperimentsat BESSY – argon band structure Argon Monomer Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010

  20. Tests andexperimentsat BESSY – argon band structure Argon Cluster (<N> = 24) Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010

  21. Tests andexperimentsat BESSY – argon band structure Argon Cluster (<N> = 42) Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010

  22. Tests andexperimentsat BESSY – argon band structure Argon Cluster (<N> = 96) Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010

  23. Tests andexperimentsat BESSY – argon band structure Argon Cluster (<N> = 190) Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010

  24. Tests andexperimentsat BESSY – argon band structure Normalizedintensity / arb. u. Monomer Surface Volume 60 61 62 kineticenergy / eV 05.02.2014 Cluster sizedistributionaccordingto Ar 3s bulk – surfaceratio Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010

  25. Tests andexperimentsat BESSY – argon band structure 05.02.2014 Comparisonoftheestimatedsizes Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010

  26. Tests andexperimentsat BESSY – argon band structure • Band dispersionisalreadyobservedforverysmallclusters! (<N> ≈ 100) • experimentallyseenforthefirst time • Dispersion isobserved in unorientedsystems • dispersionalongL, X andotherdirectionsareverysimilar, or • onlycorrectlyorientedclustersareselected Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010

  27. Tests andexperimentsat BESSY 05.02.2014 • Bottleworksfineforphotoelectronspectroscopy • Energyresolution E/E ofabout 20 achieved • Nowwhataboutelectron - electroncoincidences? • Tests madeusingforexample Xenon NOO Augerdecay • Will showmoreinterestingexperiment… Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010

  28. Tests andexperimentsat BESSY – ETMD • ETMD so faronlytheoreticallydescribed • Twoelectronsaregenerated • Coincidencemeasurement! • Twoionicfragments • In Ar-Krotherchannelsaresupressed (ICD) ETMD(3) Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010

  29. Tests andexperimentsat BESSY – ETMD Ar-Krcluster (5% Krcoexpansion) hv = 37eV Ar 3p Kr 4s Ar 3s counts Kr 4p Ar 3s bulkandsurface T.O.F. / channel 05.02.2014 Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010

  30. Tests andexperimentsat BESSY – ETMD Clusters: Kr core, Ar shell Coincidence Counts Ar 3p inelastic scattering Ar 3s cluster component time-of-flight (electron 1) Ar 3p (random coinc.) time-of-flight (electron 2) 05.02.2014 Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010

  31. Tests andexperimentsat BESSY – ETMD Preliminary hv = 32eV 05.02.2014 Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010

  32. Tests andexperimentsat BESSY – ETMD • First directspectroscopicobservationof ETMD • High detectionefficiency (almost 4 acceptance angle) • Detectionoflowkineticenergyelectrons • Very well suitedforcoincidencemeasurements… 05.02.2014 Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010

  33. New experimentsandtestsat TIFF • back to TIFFtotestimprovements • So farrestingtarget.. • Ion beam (E_kinaround 4400eV) • Measurementsat TIFF using an opticallasersystem • Magneticbottle plus neutral detectorbehindinteractionregion • electron – neutral coincidences 05.02.2014 Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010

  34. New experimentsandtestsat TIFF • back to TIFFtotestimprovementsusing OH- beam • New beamfinderandoverlapfindingprocedure • Improvedelectronspectrometer • Countrates (normalizedtophotonfluxfromopticallaser / targetdensity): Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010

  35. New experimentsandtestsat TIFF Electronvelocity due to Doppler shift = |ve|=sqrt(|vei|2+|vi|2+2cos()|vei||vi|) Withvei= electronvelocityasseenfrom restingtarget electron  Ion beam (vi) Additionally: Electron angular distribution = P(,)dcos()=[0.5- /4+0.75 cos2()]dcos() With = anisotropyparameter 05.02.2014 Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010

  36. New experimentsandtestsat TIFF • Testthis on O- • 266nm (4.7 eV) / 10 Hz laser • ~ 4400 eV / 3 nAion beam 2P 1D 3P 1.23eV 3.23eV hv + O- O + e- 05.02.2014 Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010

  37. New experimentsandtestsat TIFF 05.02.2014 Fast ion beam experimentswithmagneticbottle well manageable Countrates ofupto 15Hz withlaserintensitycomparabletothatof FLASH Doppler shift plus 4 detection angle evenallowdirectmeasurementofbetaparameters Neutral detectorallowscoinc. measurements… Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010

  38. Plannedexperimentsat FLASH 05.02.2014 • Beamtimeat FLASH end of 2010 • proposedtargets: • (H2O)nH+ • Photoelectronspectraofmassselectedclusters! • characterizationofautoionizationprocesses (ICD) • Future targets: • (H2O)n- • (H2O)nLi+ Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010

  39. Plannedexperimentsat FLASH 05.02.2014 • Improvements…: • opticallaser plus FLASH (alignmentofbottleandbeams) • improvedresolutionof mag. bottle • neutral detectorforcoincanalysis (BG reduction) • newbeamfinderbased on experiencesgainedwithanionexperiments • improvedvacuumsetup • interpretationsupportedbysimulations • FLASH improvements: • higherintensity (upto 100 J (was 20)) • morebunches (100 Bunches (was 30) ) • higherrep. rate (10Hz (was 5)) Mag. bottle electron spectroscopy on an ion beam at FLASH Heidelberg 2010

  40. Acknowledgements • FLASH experimentsand • electrondetachment: • C. Domesle • B. Jordon-Thaden • S. Klumpp • L. Lammich • M. Martins • H. B. Pedersen • A. Wolf • FLASH TEAM • Argon Bands: • O. Björneholm • P. Feulner • K. Horn • D. Menzel • G. Öhrwall • M. Scheffler • A. Stampfl • G.P. Williams • BESSY SUPPORT • Our Group: • T. Arion • S. Barth • A. Bradshaw • U. Hergenhahn • T. Lischke • M. Mucke • H.-P. Rust • V. Ullrich • ETMD: • L.S. Cederbaum • N. Sisourat • BESSY SUPPORT • Financial support: • DFG • ASG der MPG • Fonds der chem. Industrie

  41. THE END

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