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| 2. |
- Andersson, L-O, et al.
(författare)
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A new neutron beam facility
- 2004
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Ingår i: Proc. of the 9th European Particle Accelerator Conference.
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Konferensbidrag (refereegranskat)
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| 3. |
- Hartman, Henrik, et al.
(författare)
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The FERRUM project: an extremely long radiative lifetime in Ti II measured in an ion storage ring
- 2003
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Ingår i: Journal of Physics B: Atomic, Molecular and Optical Physics. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 36, s. 197-202
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Tidskriftsartikel (refereegranskat)abstract
- We have extended the laser probing technique at the CRYRING storage ring to measurement of the extremely long lifetime (28 s) of the metastable 3d2(3P)4s b 4P5/2 level in Ti II. The result obtained demonstrates the power of this method for investigation of such long-lived levels. This is the first experimental lifetime investigation of metastable states in Ti II.
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| 4. |
- Hartman, Henrik, et al.
(författare)
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The FERRUM Project: Experimental transition probabilities of [Fe II] and astrophysical applications
- 2003
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Ingår i: Astronomy & Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 397:3, s. 1143-1149
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Tidskriftsartikel (refereegranskat)abstract
- We report on experimental transition probabilities for thirteenforbidden [Fe II] lines originating from three different metastable FeIi levels. Radiative lifetimes have been measured of two metastablestates by applying a laser probing technique on a stored ion beam.Branching ratios for the radiative decay channels, i.e. M1 and E2transitions, are derived from observed intensity ratios of forbiddenlines in astrophysical spectra and compared with theoretical data. Thelifetimes and branching ratios are combined to derive absolutetransition probabilities, A-values.We present the first experimental lifetime values for the two Fe IIlevels a4G9/2 and b2H11/2and A-values for 13 forbidden transitions froma6S5/2, a4G9/2 andb4D7/2 in the optical region. A discrepancybetween the measured and calculated values of the lifetime for theb2H11/2 level is discussed in terms of levelmixing. We have used the code CIV3 to calculate transitionprobabilities of the a6D-a6S transitions.We have also studied observational branching ratios for lines from 5other metastable Fe II levels and compared them to calculated values. Aconsistency in the deviation between calibrated observational intensityratios and theoretical branching ratios for lines in a wider wavelengthregion supports the use of [Fe II] lines for determination of reddening.
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| 5. |
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| 6. |
- Johansson, Sveneric, et al.
(författare)
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The FERRUM Project: New f-value Data for Fe II and Astrophysical Applications
- 2002
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Ingår i: Physica Scripta. - : Institute of Physics Publishing (IOPP). - 0281-1847 .- 0031-8949 .- 1402-4896. ; T100, s. 71-80
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Konferensbidrag (refereegranskat)abstract
- We present the FERRUM Project, an international collaboration aiming at a production and evaluation of oscillator strengths (transition probabilities) of selected spectral lines of singly ionized iron group elements, that are of astrophysical relevance. The results obtained include measurements and calculations of permitted and forbidden lines of Fe II. The data have been applied to both emission and absorption lines in astrophysical spectra. We make comparisons between experimental, theoretical and astrophysical f-values. We give a general review of the various measurements, and discuss the UV8 multiplet of Fe II around 1610 Šin detail.
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| 7. |
- Rostohar, D, et al.
(författare)
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Experimental INvestigation of radiative decay rates of metastable levels in Eu II
- 2001
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Ingår i: Physica Scripta. - 0031-8949. ; 64, s. 237-237
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Tidskriftsartikel (refereegranskat)abstract
- The radiative lifetimes of the metastable a 9DJ (J = 2-5) levels in Eu II have been measured by laser probing of a stored ion beam. The lifetimes of all four J levels are slightly above 1 s. A deviation from the expected energy dependence of the decay rates for electric quadrupole transitions is observed and discussed.
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| 8. |
- Rostohar, D, et al.
(författare)
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Lifetime measurements of Metastable States in Fe
- 2001
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Ingår i: Physical Review Letters. - 1079-7114. ; 86, s. 1466-1466
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Tidskriftsartikel (refereegranskat)abstract
- The lifetime of two metastable levels in Fe+ has been measured by laser probing of a stored ion beam. In the dense spectrum of Fe+, the metastable levels a 6S5/2 and b 4D7/2 were selected and their lifetimes were determined to be 230+/-30 and 530+/-30 ms, respectively. The lifetimes are compared with previous theoretical results. Metastable lifetime measurements of Fe+ are of great importance for interpretation of spectra from astronomical objects. The present experiment opens for the possibilities to investigate lifetimes of metastable states in complex atomic ions, which have, so far, been unexplored.
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| 9. |
- Rostohar, D, et al.
(författare)
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Studies of lifetimes in an ion storage ring using laser technique
- 2003
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Ingår i: Hyperfine Interactions. - 1572-9540 .- 0304-3843. ; 146:1-4, s. 151-159
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Konferensbidrag (refereegranskat)abstract
- The laser-probing method for lifetime measurements of metastable levels, performed by applying the Fast Ion Beam Laser (FIBLAS) method to ions stored in a storage ring, has been developed by the Stockholm group. Recently, we have applied this method to lifetime measurements of close lying metastable levels. In this paper we discuss experimental studies of ions with complex structure and present the first experimentally obtained lifetimes of selected metastable levels in complex systems as Fe+, Eu+ and La+.
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| 10. |
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