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Synchrotron Radiation based TDPAC

CERN. Synchrotron Radiation based TDPAC. I. Sergueev European Synchrotron Radiation Facility Grenoble, France. ESRF. Outline. SR TDPAC: comparison with conventional TDPAC SR TDPAC: comparison with MS and NRS Examples of application: Site-specific phonon dynamics

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Synchrotron Radiation based TDPAC

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  1. CERN Synchrotron Radiation based TDPAC I. Sergueev European Synchrotron Radiation Facility Grenoble, France ESRF HFI / NQI 2010, 12-17 September 2010 CERN

  2. Outline • SR TDPAC: comparison with conventional TDPAC • SR TDPAC: comparison with MS and NRS • Examples of application: • Site-specific phonon dynamics • Relaxation in glasses • Study of QI in -tin • Conclusion HFI / NQI 2010, 12-17 September 2010 CERN

  3. life time of the excited state - 0 excited state re-emission absorption ground state Nuclear Resonance Scattering Time Time A.Q.Baron et al, Europhys. Lett.,34, 331(1996) I.Sergueev et al, Phys. Rev. B 73, 024203 (2006) I.Sergueev et al. Phys. Rev. B 78, 214436 (2008) HFI / NQI 2010, 12-17 September 2010 CERN

  4. TDPAC vs SR TDPAC β-,β+,EC • Advantages of SR TDPAC: • no chemical or electronic aftereffects • only one nuclear transition • in general, large contrast of the beats 1 1 2 2 SRPAC TDPAC sample (-source) 1 1 2 sample 2 SR detector 1 detector 2 detector counter counter start stop start stop HFI / NQI 2010, 12-17 September 2010 CERN

  5. Z  kout kin  Formal description of SR TDPAC for M1 TDPAC SR TDPAC Z k2 k1  HFI / NQI 2010, 12-17 September 2010 CERN

  6. Sample: α-iron enriched by 57Fe with magnetic splitting Sample: ferrocene enriched by 57Fe with quadrupole splitting SR TDPAC on 57Fe Z Z  1 2  kout kin 3 kin B kout 1 2 3 HFI / NQI 2010, 12-17 September 2010 CERN

  7. D. H. Ryan and J.M.Cadogan, Hyp. Int. 153 (2004) 43 SR TDPAC for E2 transition Nuclear transition : 0+ 2+, Cascade: 0  2  0 166ErFe6Sn6 HFI / NQI 2010, 12-17 September 2010 CERN

  8. High Resolution Monochromator Sample Detector Monochromator Al foil Undulator Detector Detector with Si APDs APD beam Experimental setup Energy band width: 1-30 meV Dynamical range: ~106 ph/s Time resolution: ~0.1-2 ns HFI / NQI 2010, 12-17 September 2010 CERN

  9. t > 0 k1 k0 k0 single nucleus scattering SR TDPAC t = 0 t = 0 SR TDPAC vs NFS nuclear bragg diffraction coherent scattering in forward direction - - nuclear forward scattering k0 t > 0 Optical theorem: MS total cross-section NFS amplitude • Differences: • dependence on the spatial evolution of nuclei • dependence on the ground nuclear state spin evolution HFI / NQI 2010, 12-17 September 2010 CERN

  10. Energy level diagram: 57Fe, quadrupole splitting |m| 3/2 1/2 I=3/2 I=1/2 1/2 Hyp. Int.: quadrupole splitting Ferrocene Coherent superposition of the wavelets HFI / NQI 2010, 12-17 September 2010 CERN

  11. Hyp. Int.: 2 single lines I=3/2 MS, NFS SR TDPAC I=1/2 HFI / NQI 2010, 12-17 September 2010 CERN

  12. Hyp. Int.: magnetic splitting m +3/2 +1/2 -1/2 -3/2 -1/2 +1/2 -iron MS, NFS SRPAC SR TDPAC NFS SR HFI / NQI 2010, 12-17 September 2010 CERN

  13. Applications • Site-specific phonon dynamics • Relaxation in glasses • Study of QI in -tin

  14. Phonon assisted SR TDPAC Handke B et al., Phys. Rev. B 71 (2005) 144301 Sample: Magnetite, Fe3O4 Weber, H., Hafner, S.S.: Z. Krist. 133 (1971) 331. A site: tetrahedral, B = 49.0 T B site: octahedral, B = 46.0 T HFI / NQI 2010, 12-17 September 2010 CERN

  15. 16 meV 22 meV B site 35 meV A site Phonon assisted SR TDPAC HFI / NQI 2010, 12-17 September 2010 CERN

  16. EFG Relaxation in glasses Sample: ferrocene Fe(C5H5)2 Glass-former: Di-butyl phthalate, Tg = 178 K Task: resolve rotational and translational degrees of motions HFI / NQI 2010, 12-17 September 2010 CERN

  17. Relaxation in glasses Relaxation process α k – jump rate, sec-1 a – jump distance α – jump angle λ – wave length, 0.86 A R – radius of the molecule, 2 A a a α λ HFI / NQI 2010, 12-17 September 2010 CERN

  18. Relaxation in glasses Sample: Di-butyl phthalate, Tg = 178 K Di isobytyl phthalate, Tg = 188 K 5% ferrocene + DiBP+FC SR TDPAC DiBP+FC NFS SR TDPAC NFS SR HFI / NQI 2010, 12-17 September 2010 CERN

  19. Relaxation in glasses DBP+FC DiBP+FC Conclusions: The probe reproduces the dynamics of the glass former. At low T dynamics of the probe follows slow β branch At low T only molecular rotation is seen in both NFS and SR TDPAC. HFI / NQI 2010, 12-17 September 2010 CERN

  20. Measurements by SR TDPAC C. Strohm et al., in preparation Study of -tin by SR TDPAC K.P.Mitrofanov et al., Sov. Phys. JETP 21 (1965) 524 J.C. Soares et al., Phys.Lett. 45A(1973)465 HFI / NQI 2010, 12-17 September 2010 CERN

  21. Study of -tin by SRPAC Results of measurements • Conclusion: • value of the life time of 23.9keV nuclear state of 119Sn was obtained with high precision • quadrupole splitting of -tin have been seen in the time spectrum and was measured for different temperatures HFI / NQI 2010, 12-17 September 2010 CERN

  22. Conclusion SR TDPAC – method which allows to extend study of hyperfine interactions by TDPAC on to Mössbauer isotopes – method which allows to extend study of hyperfine interactions by MS into the range of zero Lamb-Mössbauer factor. 3 main directions of application: Complementary to MS information about hyperfine splitting and dynamics Hyperfine interactions in high energy Mössbauer isotopes Study of hyperfine interactions and dynamics in soft condensed matter HFI / NQI 2010, 12-17 September 2010 CERN

  23. Acknowledgment • U. Van Bürck – TU München, Germany • G. Smirnov – Kurchatov Institute, Moscow, Russia • Members of ESRF nuclear resonance group: • R. Rüffer • A. Chumakov • T. Asthalter • C. Strohm • T. H. Deschaux-Beaume HFI / NQI 2010, 12-17 September 2010 CERN

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