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Experiments with magnetic bottles

Experiments with magnetic bottles. Melanie Mucke Department of Physics and Astronomy Uppsala University, Sweden (melanie.mucke@physics.uu.se). outline. part 1: magnetic bottle spectrometer working principle layout features part 2: synchrotron experiments coincidences

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Experiments with magnetic bottles

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  1. Experiments with magnetic bottles Melanie Mucke Department of Physics and Astronomy Uppsala University, Sweden (melanie.mucke@physics.uu.se)

  2. outline • part 1: magnetic bottle spectrometer • working principle • layout • features • part 2: synchrotron experiments • coincidences • ICD in water clusters • part 3: FEL experiments • covariance technique with neon • double core holes in hydrocarbons • pump-probe on thymine

  3. part 1: magnetic bottle

  4. magnetic bottle – the beginning Kruit and Read, J. Phys. E 16, 313 (1983): cylindrical poles of electromagnet around interaction region, drift tube with coild around for homogeneous guiding field, detector: MCP + phosphor screen e- strong magnetic field Bi weak magnetic field Bf v v e- qi qf z

  5. magnetic bottle - principle Bi Bf Lorentz force v angular frequency of motion v qi qf orbit (cyclotron radius) angular momentum of circular motion

  6. magnetic bottle - principle Bi Bf Lorentz force adiabatic transition v angular frequency of motion v qi qf orbit (cyclotron radius) angular momentum of circular motion e.g. Bi = 1 T, Bf = 1 mT qf,max = 1.8°, M = 31.6

  7. magnetic bottle – as used replace electromagnet by permanent magnet  increase solid angle from 2p to 4p e- e- permanent magnet inhomogeneous, strong field (0,4 T) solenoid homogeneous, weak field (0,5 mT)

  8. magnetic bottle – special features • time-of-flight spectrometer – cover full kinetic energy range • high transmission over large kinetic energy range • high detection efficiency • capable of multi particle detection •  ideally suited to investigate correlation between electrons

  9. hn = IR … 10 kV d = 76 m one electron bunch approx. 20 mA part 2: experiments at BESSY • time of flight spectra •  need pulsed light source •  need start signal • need to calibrate BESSY II rep. rate 1.25 MHz = 800.5 ns revolution time

  10. experimental setup synchrotron radiation magnetic tip mesh flight tube (0.6 m) with homogeneous magnetic field detector flange with MCP stack & phosphor screen cluster beam joint project with AG Becker, FHI Berlin

  11. water clusters ... between molecule and liquid B. Hartke, Angew. Chem. Int. Ed. 41, 1468 (2002).

  12. Intermolecular Coulombic Decay continuum 12,85 - 19,11 outer valence inner valence 33,37 binding energy (eV) core level monomer energies for water follow I. Müller and L. Cederbaum, JCP 125, 204305 (2006).

  13. Intermolecular Coulombic Decay continuum 12,85 - 19,11 11,91 - 19,74 outer valence 32,59 - 34,10 inner valence 33,37 binding energy (eV) core level monomer dimer energies for water follow I. Müller and L. Cederbaum, JCP 125, 204305 (2006).

  14. Intermolecular Coulombic Decay continuum 12,85 - 19,11 11,91 - 19,74 outer valence 32,59 - 34,10 inner valence 33,37 double ionisation potential „one-site“ 38,63 eV double ionisation potential „two-site“ 27,97 eV binding energy (eV) core level monomer dimer energies for water follow I. Müller and L. Cederbaum, JCP 125, 204305 (2006).

  15. ICD in water clusters calculation for water tetramer energy spectrum of the ICD-electron: I. Müller and L. S. Cederbaum, JCP 125, 204305 (2006).

  16. photoelectron spectrum of water outer valence inner valence cluster contribution S. Barth et al., JPC A 113, 13519 (2009).

  17. photoelectron spectrum of water outer valence inner valence This state can decay via ICD. cluster contribution + ICD electrons S. Barth et al., JPC A 113, 13519 (2009).

  18. electron-electron coincidence measurement fast investigate coincident electron pairs electrons undistinguishable sort by flighttime slow flight time electron 2 flight time electron 1

  19. neon tof-map

  20. time-to-energy conversion flight time electron 2 flight time electron 2 flight time electron 1 flight time electron 2

  21. coincidence maps of water tof map energy map flight time e1 kinetic energy e1 flight time e2 kinetic energy e2 hn = 45 eV

  22. ICD spectrum energy spectrum shows ICD 0  qualitative agreement with theoretical spectrum expected range for water ICD hn = 45 eV <N> = 40

  23. spectrum of the intermediate state 0 energy spectrum of the primary electrons vs. kinetic energy hn = 45 eV <N> = 40

  24. spectrum of the final state 0 coincident intensity vs. binding energy of the final state DIP H2O monomer hn = 45 eV <N> = 40

  25. variation of the excitation energy • ICD feature shifts with photon energy • energy of the ICD electron follows the theoretical predictions M. Mucke et al., Nature Phys. 6, 143 (2010)

  26. no ICD in the monomer cluster monomer hn = 60 eV <N> = 200 M. Mucke et al., Nature Phys. 6, 143 (2010)

  27. part 3: experiments at the LCLS LCLS start injector Experiment and UV laser ~1500 m

  28. large collaborations at LCLS Uppsala University M. Mucke V. Zhaunerchyk M. Kaminska M.N. Piancastelli J.H.D. Eland (also Oxford University) R. Feifel SLAC R. Coffee M. Glownia J. Cryan M. Messerschmidt S. Schorb C. Bostedt J. Bozek Stockholm University P. Salén P. v.d.Meulen P. Linusson R.D. Thomas M. Larsson ELETTRA Trieste R. Richter K.C. Prince Imperial College London R.J. Squibb (now Uppsala University) M. Siano L.J. Frasinski Tohoku University, Sendai K. Motomura S. Mondal K. Ueda Michigan University T. Osipov L. Fang B. Murphy N. Berrah Hiroshima University O. Takahashi S. Wada MPI, Heidelberg L. Foucar J. Ullrich

  29. a new bottle...

  30. experiments at the LCLS AMO hutch High Field Physics chamber Aug/Sep 2011 spectrometer axis FEL beam rep. rate 120 Hz sample beam

  31. experimental set-up solenoid magnet online display e- e- digitiser FEL MCP sample trigger from FEL pulse parameters

  32. covariance analysis • difference in correlated and uncorrelated products of electron signals X and Y at two kinetic energies: • C(X,Y) = <XY> - <X><Y> • jitter corretion (photon energy fluctuation) • partial covariance corrects for intensity fluctuations of FEL: • Cp(X,Y;I) = C(X,Y) - C(X,I)C(I,Y)/C(I,I) • conditional covariance: groupwise analysis of data from shots of similar intensity L.F. Frasinski et al., Science 246, 1029 (1989). L.F. Frasinski et al., J. El. Spec. Rel. Phenom. 79, 367 (1996). V. Zhaunerchuk et al., Phys. Rev. A 89, 053418 (2014).

  33. Double Core Holes creation of two core holes in a molecule by photon impact at the same atom ss DCH increased orbital relaxation effect at different atoms ts DCH high sensitivity to chemical environment from L.S. Cederbaum et al., Chem. Phys. 85, 6513 (1986).

  34. recent studies on DCHs synchrotron radiation + multi-particle coincidence FEL+ single-electron detection CH4 C 1s-2 NH3 N 1s-2 L. Fang et al., Phys. Rev. Lett. 105, 083005 (2010), J. Cryanet al., Phys. Rev. Lett105, 083004 (2010), N. Berrahet al., PNAS 108, 16912 (2011), P. Salénet al., Phys. Rev. Lett. 108, 153003 (2012), M. Larsson et al., J. Phys. B 46, 164034 (2013). J.H.D. Eland et al., Phys. Rev. Lett. 105, 213005 (2010), P. Lablanquieet al., Phys. Rev. Lett. 106, 063003 (2011), P. Linussonet al., Phys. Rev. A 83, 022506 (2011), P. Lablanquieet al., Phys. Rev. Lett. 107, 193004 (2011), M. Nakano et al., Phys. Rev. Lett. 110, 163001 (2013), L. Hedin et al., J. Chem. Phys., submitted (2013).

  35. study of DCHs at FELs • use efficient electron spectrometer, • employ covariance technique • make up for low repetition rate of FEL pulses by • allowing for multiple ionisation events per light pulse • using a spectrometer of high detection efficiency • being able to handle multiple electrons per ionisation event

  36. study of DCHs at FELs • use efficient electron spectrometer, • employ covariance technique • make up for low repetition rate of FEL pulses by • allowing for multiple ionisation events per light pulse • using a spectrometer of high detection efficiency • being able to handle multiple electrons per ionisation event ”core hole clock”: FEL pulse length vs. core hole lifetime  get information on ionisation dynamics

  37. neon: ionisation processes photon energy 1062 eV

  38. neon: covariance map core-region FEL parameters 40 pC charge mode 0.35 mJ pulse energy ≤ 10 fs pulse length 1062 eV photon energy

  39. neon: covariance map correction jitter corrected raw data V. Zhaunerchyk, M. Mucke,…, and R. Feifel, J. Phys. B 46, 164034 (2013). disciminated data Fourier deconvolution

  40. neon: coincidence vs. covariance coincidence covariance V. Zhaunerchyk, M. Mucke, et al., J. Phys. B 46, 164034 (2013).

  41. neon: covariance map core-region FEL parameters 40 pC charge mode 0.35 mJ pulse energy ≤ 10 fs pulse length 1062 eV photon energy

  42. neon: covariance map core-region FEL parameters 40 pC charge mode 0.35 mJ pulse energy ≤ 10 fs pulse length 1062 eV photon energy autocorrelation line 1 3 6 1 PAP 2 PP or PAPAP 3 PAPVP, PPVAP or PAPsat 4 PAPAP 5 DKV 6 DKVAP 4 2 5

  43. neon: covariance maps 7 core-valence region core-core region autocorrelation line autocorrelation line 1 1 6 3 3 6 8 4 4 2 2 1 PAP 2 PP or PAPAP 3 PAPVP, PPVAPor PAPsat 4 PAPAP 5 DKV 6 DKVAP 7 PVP 8 PAPVP or PPVAP  first time distinguish PPV from PVP L.J. Frasinski et al., Phys. Rev. Lett. 111, 073002 (2013), V. Zhaunerchyk et al., J. Phys. B 46, 164034 (2013). 5 5

  44. Double Core Holes in hydrocarbons These slides have been deleted since the results are not yet published. If you want information on the outcomes of our investigation of double core hole states in hydrocarbons (C2H2 and C2H6) at the LCLS, please contact me (melanie.mucke@physics.uu.se).

  45. summary on Double Core Holes • 2dim covariance well suited for analysis of data from low repetition-rate light sources (handling of multiple ionisation events per light shot possible) • identification of new few-photon processes by electron kinetic energies and comparison of intensity dependency of electron-pair features • clear signatures for DCHs

  46. ultrafast processes in thymine ... investigated by pump-probe spectroscopy Dt UV pump + XFEL probe magnetic bottle Auger difference spectra

  47. thymine collaboration Early Career Grant Reference: McFarland et al. Nature Comm. 5, 4235 (2014)

  48. competing processes np* GS->pp* p* Potential energy Barrier? n 4.5 eV p pp* np* UV pump Ground state Reaction coordinate Asturiolet al., J. Phys. Chem. A,113, 10211 (2009) Hudocket al., J. Phys. Chem. A,111, 85 (2007)

  49. pump-probe scheme np* Electr. Relax. Ekin p* Core ionized states IP GS->pp* Auger decay Ekin n UV pump Potential energy SXR probe Dicationic states GS p SXR probe Barrier? Electr. Relax. pp* Oxygen 1s CI O CI UV pump np* Neutral states Ground state X-ray probe Auger decay Delay UV pump O Reaction coordinate

  50. Auger difference spectra Difference signal: UV On-UV Off UV pump: 266 nm XFEL probe: 570 eV retardation 470 V UV Pump Off UV Pump On p*Auger Electrons

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