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Storage ring measurements of the dissociative recombination of H 3 + : a closer look

Storage ring measurements of the dissociative recombination of H 3 + : a closer look. Holger Kreckel University of Illinois at Urbana-Champaign. TSR Group. University of Illinois. Kyle N. Crabtree Brian A. Tom Benjamin J. McCall. Old ř ich Novotny* Annemieke Petrignani Max H. Berg

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Storage ring measurements of the dissociative recombination of H 3 + : a closer look

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  1. Storage ring measurements of the dissociative recombination of H3+: a closer look Holger Kreckel University of Illinois at Urbana-Champaign TSR Group University of Illinois Kyle N. Crabtree Brian A. Tom Benjamin J. McCall Oldřich Novotny* Annemieke Petrignani Max H. Berg Dennis Bing Manfred Grieser Claude Krantz Michael Lestinsky* Mario B. Mendes Christian Nordhorn Roland Repnow Julia Stützel Andreas Wolf Weizmann Institute Henrik Buhr Stockholm University Richard Thomas *Columbia University, NY

  2. DR 2010, Lake Tahoe, Aug19th 2010 Holger Kreckel H He Ne O C N Si S Ar Mg Fe Storage ring measurements … of H3+: a closer look The relevance of H3+: astronomer‘s periodic table

  3. DR 2010, Lake Tahoe, Aug19th 2010 Holger Kreckel Storage ring measurements … of H3+: a closer look The relevance of H3+: engine of interstellar chemistry H3+ formation H2 + c.r. H2++ e- H2+ + H2 H3+ + H Proton-hop reactions H3+ + X XH+ +H2

  4. DR 2010, Lake Tahoe, Aug19th 2010 Holger Kreckel  [H2] Cosmic ray ionization rate [H3+] = [e-] ke DR rate coefficient Storage ring measurements … of H3+: a closer look The enigma of H3+ in diffuse clouds Steady State:

  5. DR 2010, Lake Tahoe, Aug19th 2010 Holger Kreckel Leu, Biondi, Johnsen (1973) Stat. afterglow McCall et al. (2003) Storage ring Larsson et al. (1993) Storage ring Amano (1988) IR spectroscopy Kreckel et al. (2005) Storage ring Adams, Smith, Alge(1984) Flow. afterglow Glosik et al.(2000-2009) Stat. & flow. afterglow Adams, Smith (1987) Flow. afterglow Storage ring measurements … of H3+: a closer look “Perceived” H3+ DR rate coefficient 10-7 10-8 H3+ DR rate coefficient at 300K 10-9 10-10 10-11 1970 2000 year 2010 1980 1990

  6. DR 2010, Lake Tahoe, Aug19th 2010 Holger Kreckel Storage ring measurements … of H3+: a closer look Storage ring measurements: concept Advantages •radiative relaxation of internal excitations (rotation, vibration) • direct measurement • 100% detection efficiency • high resolution Problem H3+ ! • radiative relaxation incomplete

  7. DR 2010, Lake Tahoe, Aug19th 2010 Holger Kreckel (1,00) theory experimental data (T > 2s) (2,00) theory (0,00) theory experimental data (T < 1ms) Storage ring measurements … of H3+: a closer look Coulomb explosion results H3+ Vibrations decay within the first 2s of storage Some rotational states stay forever Kreckel et al., PRA 66, 052509 (2002)

  8. DR 2010, Lake Tahoe, Aug19th 2010 Holger Kreckel 5 cm Pinhole flange/ground electrode -900 V ring electrode TSR 2004 Cryogenic ion trap H3+ Storage ring measurements … of H3+: a closer look “Cold” ion sources Gas inlet 2 atm H2 Solenoid valve CRYRING 2002 Supersonic expansion

  9. DR 2010, Lake Tahoe, Aug19th 2010 Holger Kreckel Storage ring measurements … of H3+: a closer look Storage ring results with “cold” H3+ ion sources ● TSR electron temp. kT┴=0.5 meV ~ 6K kT||=25 μeV trap temp. 13 K Kreckel, PRL 95, 263201 (2005) ●CRYRING kT┴=2 meV ion temp. 30-50 K McCall, Nature 422, 500 (2003) Theory Kokoouline and Greene

  10. DR 2010, Lake Tahoe, Aug19th 2010 Holger Kreckel + + Storage ring measurements … of H3+: a closer look The holy grail: state specific measurements para I = 1/2 ortho I = 3/2 H3+ rotational levels

  11. DR 2010, Lake Tahoe, Aug19th 2010 Holger Kreckel Storage ring measurements … of H3+: a closer look Nuclear spin effect: exp. and theory 2005 ۰para H2 ۰normal H2 experiment kT┴=4 meV theory Greene et al. - para - ortho Kreckel et. al, PRL 95, 263201 (2005)

  12. DR 2010, Lake Tahoe, Aug19th 2010 Holger Kreckel Storage ring measurements … of H3+: a closer look Theory with more accurate resonance energies S. Fonseca dos Santos et al., JCP 127, 124309 2007

  13. DR 2010, Lake Tahoe, Aug19th 2010 Holger Kreckel Reduced rate coeff. Storage ring measurements … of H3+: a closer look Quantifying nuclear spin effects B. Tom et al., JCP 130, 031101 2009

  14. DR 2010, Lake Tahoe, Aug19th 2010 Holger Kreckel plunger locking nut discharge electrode skimmer high pressure H2 reservoir low pressure pinhole 6 cm piezo actuator Storage ring measurements … of H3+: a closer look Piezo expansion source

  15. DR 2010, Lake Tahoe, Aug19th 2010 Holger Kreckel Difference frequency generation: 3.67 μm Storage ring measurements … of H3+: a closer look Cavity ring down measurements at UIUC

  16. DR 2010, Lake Tahoe, Aug19th 2010 Holger Kreckel HG Storage ring measurements … of H3+: a closer look Transitions observed

  17. DR 2010, Lake Tahoe, Aug19th 2010 Holger Kreckel Storage ring measurements … of H3+: a closer look Rotational temperature pure H2 discharge, 2bar Trot=110 K No vibrations found! 1:5 H2:Argon discharge, 2bar Trot=180 K

  18. DR 2010, Lake Tahoe, Aug19th 2010 Holger Kreckel para H3+ para H3+ ortho H3+ p-H3+ fraction p3= (47.9 ± 2) % 1:5 n-H2 : Argon mixture p-H3+ fraction p3= (70.8 ± 2) % 1:5 p-H2 : Argon mixture Storage ring measurements … of H3+: a closer look Nuclear spin manipulation

  19. DR 2010, Lake Tahoe, Aug19th 2010 Holger Kreckel Storage ring measurements … of H3+: a closer look DR measurements at TSR UI Champaign-Urbana MPI-K Heidelberg Test Storage Ring

  20. DR 2010, Lake Tahoe, Aug19th 2010 Holger Kreckel electron density electron target length storage ring circumference electron beam switched off Storage ring measurements … of H3+: a closer look Absolute scale of the rate coefficient

  21. DR 2010, Lake Tahoe, Aug19th 2010 Holger Kreckel Storage ring measurements … of H3+: a closer look Comparison to CRYRING 2002 TSR 2009 (n-H2:Ar 1:5) CRYRING 2002 (n-H2)

  22. DR 2010, Lake Tahoe, Aug19th 2010 Holger Kreckel δt 1 m P(D) 3-dimensional imaging, point source 2-dimensional imaging, point source 2-dimensional imaging, extended source d ~ √Ek Storage ring measurements … of H3+: a closer look Rotational temperature: imaging basics H2+ + e- d detector beam vel.

  23. DR 2010, Lake Tahoe, Aug19th 2010 Holger Kreckel ne(cooler) = 1.4 x 107 cm-3 ne(target) = 1.34 x 106 cm-3 expected KER = 4.79 eV Storage ring measurements … of H3+: a closer look 2-dimensional imaging of the 3-body breakup H3+ + e- H + H + H

  24. DR 2010, Lake Tahoe, Aug19th 2010 Holger Kreckel rotational temperatures (uncertainties ~ 200 K) 950 K 450 K 200 K Storage ring measurements … of H3+: a closer look 2-dimensional imaging of the 3-body breakup H3+ + e- H + H + H

  25. DR 2010, Lake Tahoe, Aug19th 2010 Holger Kreckel Storage ring measurements … of H3+: a closer look Piezo source extraction potentials

  26. DR 2010, Lake Tahoe, Aug19th 2010 Holger Kreckel skimmer Storage ring measurements … of H3+: a closer look Conditions on-axis downstream of the nozzle Collisional heating during Ion extraction?

  27. DR 2010, Lake Tahoe, Aug19th 2010 Holger Kreckel Storage ring measurements … of H3+: a closer look Detailed comparison of the (reduced) rate coefficient TSR / 22-pole trap 2007 CRYRING / Solenoid 2002 TSR / piezo 2009

  28. DR 2010, Lake Tahoe, Aug19th 2010 Holger Kreckel Reduced rate coeff. Storage ring measurements … of H3+: a closer look Nuclear spin dependence of the rate coefficient p3= (47.9 ± 2) % 1:5 n-H2 : Argon mixture p3= (70.8 ± 2) % 1:5 p-H2 : Argon mixture Extrapolation: 100% ortho H3+ 100% para H3+

  29. DR 2010, Lake Tahoe, Aug19th 2010 Holger Kreckel Still out there … Storage ring measurements … of H3+: a closer look Summary • While we measure a rotational temperature of 200K with CRD spectroscopy, the stored H3+ ions are much hotter than the ion source. • We observed clear differences between different ion sources → the heating is probably happeningprior to injection into the ring. • We observed for the first time detailed structures in the rate coefficients for ortho-H3+ and para-H3+ at low energies. Results: Kreckel et al., submitted to PRA Petrignani et al., in preparation The holy grail?

  30. DR 2010, Lake Tahoe, Aug19th 2010 Holger Kreckel Storage ring measurements … of H3+: a closer look Perspectives: the case to continue the quest It is crucial to understand: H3+ + H2 and H3+ (J=1,K=0,1) + e- Kyle N. Crabtree et al., to be published

  31. DR 2010, Lake Tahoe, Aug19th 2010 Holger Kreckel Storage ring measurements … of H3+: a closer look Collaboration TSR Group University of Illinois Kyle N. Crabtree Brian A. Tom Benjamin J. McCall Oldřich Novotny* Annemieke Petrignani Max H. Berg Dennis Bing Manfred Grieser Claude Krantz Michael Lestinsky* Mario B. Mendes Christian Nordhorn Roland Repnow Julia Stützel Andreas Wolf Weizmann Institute Henrik Buhr Stockholm University Richard Thomas *Columbia University, NY German-Israeli Foundation National Science Foundation Max-Planck Society Funding: Eurppean Comission

  32. DR 2010, Lake Tahoe, Aug19th 2010 Holger Kreckel Storage ring measurements … of H3+: a closer look

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