First experiments with the heidelberg test storage ring TSR

Habs, D.; Baumann, Werner; Berger, J.; Blatt, P.; Faulstich, A.; Krause, Pascal; Kilgus, G.; Neumann, R.; Petrich, Wolfgang; Stokstad, R. G.; Schwalm, D.; Szmola, E.; Welti, K.; Wolf, A.; Zwickler, S.; Jaeschke, E.; Krämer, D.; Bisoffi, G.; Blum, Monika; Friedrich, Alexander; Geyer, C.; Grieser, M.; Heyng, H.W.; Hölzer, B.; Ihde, R.; Jung, Matthias; Matl, K.; Ott, William R.; Povh, Bogdan; Repnow, R.; Steck, M.; Steffens, E.; Dutta, D.P.; Kühl, T.; Marx, D.; Schröder, S.; Gerhard, M.; Grieser, R.; Huber, G.; Klein, Richard; Krieg, M.; Schmidt, Nadine; Schuch, R.; Babb, James F.; Spruch, Larry; Arnold, W.; Noda, Akira

doi:10.1016/0168-583x(89)90383-2

Cited by 112 publications

(16 citation statements)

References 26 publications

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“…Experimental studies were carried out at the storage-ring TSR at the Max-Planck-Institut für Kernphysik in Heidelberg [16,17]. For the rotationally cool H 3 + measurements, the ions were produced in a radio-frequency (rf) storage ion source and buffer gas cooled for 1 ms in a cryogenic 22-pole ion trap at a helium density of 10 16 cm −3 and a temperature of ∼15 K. It has been shown through spectroscopy measurements and modeling [7,18] that the cooling of the H 3 + in the 22-pole trap is efficient and produces ions with rotational and translational temperatures that agree well with the nominal trap tempera-ture.…”

Section: Methodsmentioning

confidence: 99%

Resonant structure of low-energyH3+dissociative recombination

et al. 2011

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High-resolution dissociative recombination rate coefficients of rotationally cool and hot H 3 + in the vibrational ground state have been measured with a 22-pole trap setup and a Penning ion source, respectively, at the ion storage-ring TSR. The experimental results are compared with theoretical calculations to explore the dependence of the rate coefficient on ion temperature and to study the contributions of different symmetries to probe the rich predicted resonance spectrum. The kinetic energy release was investigated by fragment imaging to derive internal temperatures of the stored parent ions under differing experimental conditions. A systematic experimental assessment of heating effects is performed which, together with a survey of other recent storage-ring data, suggests that the present rotationally cool rate-coefficient measurement was performed at 380 +50 −130 K and that this is the lowest rotational temperature so far realized in storage-ring rate-coefficient measurements on H 3 + . This partially supports the theoretical suggestion that temperatures higher than assumed in earlier experiments are the main cause for the large gap between the experimental and the theoretical rate coefficients. For the rotationally hot rate-coefficient measurement a temperature of below 3250 K is derived. From these higher-temperature results it is found that increasing the rotational ion temperature in the calculations cannot fully close the gap between the theoretical and the experimental rate coefficients.

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Section: Methodsmentioning

confidence: 99%

Resonant structure of low-energyH3+dissociative recombination

et al. 2011

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“…The DR measurements were carried out at the TSR storage ring of the Max-Planck-Institut für Kernphysik in Heidelberg, Germany [23]. The storage ring consists of an octagon-shaped ion orbit surrounded by an ultra-high-vacuum chamber of 55.4 m circumference with a base pressure of ∼10 −11 mbar, providing a clean environment for electron collision experiments.…”

Section: A Storage-ring Techniquementioning

confidence: 99%

High-resolution storage-ring measurements of the dissociative recombination ofH3+using a supersonic expansion ion source

et al. 2010

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We have performed measurements of the dissociative electron recombination (DR) of H + 3 at the ion storage ring TSR utilizing a supersonic expansion ion source. The ion source has been characterized by continuous wave cavity ring-down spectroscopy. We present high-resolution DR rate coefficients for different nuclear spin modifications of H + 3 combined with precise fragment imaging studies of the internal excitation of the H + 3 ions inside the storage ring. The measurements resolve changes in the energy dependence between the ortho-H + 3 and para-H + 3 rate coefficients at low center-of-mass collision energies. Analysis of the imaging data indicates that the stored H + 3 ions may have higher rotational temperatures than previously assumed, most likely due to collisional heating during the extraction of the ions from the ion source. Simulations of the ion extraction shed light on possible origins of the heating process and how to avoid it in future experiments.

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“…To address the needs for modeling photoionized gases, we are carrying out a series of experiments to measure the ∆n = 0 DR rates for the iron L-shell ions. Measurements are performed using the heavy-ion Test Storage Ring (TSR) at the Max-Planck-Institute for Nuclear Physics in Heidelberg, Germany (Habs et al 1989;Kilgus et al 1992). In Savin et al (1997), we gave a summary of our measurements for Fe XVIII.…”

Section: )mentioning

confidence: 99%

Dielectronic Recombination in Photoionized Gas. II. Laboratory Measurements for Fe xviii and Fe xix

Savin

Kahn

Linkemann

et al. 1999

ASTROPHYS J SUPPL S

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In photoionized gases with cosmic abundances, dielectronic recombination (DR) proceeds primarily via nlj → nl ′ j ′ core excitations (∆n = 0 DR). We have measured the resonance strengths and energies for Fe XVIII to Fe XVII and Fe XIX to Fe XVIII ∆n = 0 DR. Using our measurements, we have calculated the Fe XVIII and Fe XIX ∆n = 0 DR rate coefficients. Significant discrepancies exist between our inferred rates and those of published calculations. These calculations overestimate the DR rates by factors of ∼ 2 or underestimate it by factors of ∼ 2 to orders of magnitude, but none are in good agreement with our results. Almost all published DR rates for modeling cosmic plasmas are computed using the same theoretical techniques as the above-mentioned calculations. Hence, our measurements call into question all theoretical ∆n = 0 DR rates used for ionization balance calculations of cosmic plasmas. At temperatures where the Fe XVIII and Fe XIX fractional abundances are predicted to peak in photoionized gases of cosmic abundances, the theoretical rates underestimate the Fe -2 -XVIII DR rate by a factor of ∼ 2 and overestimate the Fe XIX DR rate by a factor of ∼ 1.6. We have carried out new multiconfiguration Dirac-Fock and multiconfiguration Breit-Pauli calculations which agree with our measured resonance strengths and rate coefficients to within typically better than ∼ < 30%. We provide a fit to our inferred rate coefficients for use in plasma modeling. Using our DR measurements, we infer a factor of ∼ 2 error in the Fe XX through Fe XXIV ∆n = 0 DR rates. We investigate the effects of this estimated error for the well-known thermal instability of photoionized gas. We find that errors in these rates cannot remove the instability, but they do dramatically affect the range in parameter space over which it forms.

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First experiments with the heidelberg test storage ring TSR

Cited by 112 publications

References 26 publications

Resonant structure of low-energyH3+dissociative recombination

Resonant structure of low-energyH3+dissociative recombination

High-resolution storage-ring measurements of the dissociative recombination ofH3+using a supersonic expansion ion source

Dielectronic Recombination in Photoionized Gas. II. Laboratory Measurements for Fe xviii and Fe xix

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