| 1. |
- Fritioff, Karin, et al.
(författare)
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Observation of an excited C2-4 ion
- 2004
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Ingår i: Journal of Physics B: Atomic, Molecular and Optical Physics. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 37:11, s. 2241-2246
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Tidskriftsartikel (refereegranskat)abstract
- This paper reports an experimental investigation of the electron impact detachment of C−4. We observe structure in the electron impact cross section for detaching a single electron from a C−4 cluster anion, which we attribute to the formation and decay of the C2−4 dianion. The system is energetically unstable and very rapidly decays via double autodetachment. The energy and width of the resonance were determined to be 8.8(5) eV and 1.4(5) eV, respectively, and the resonance lies 1.5(5) eV above the ground state of the neutral system. The experiment was conducted by merging monoenergetic electron and ion beams in the heavy ion storage ring CRYRING. The detachment channel was monitored by detecting neutral C4 fragments.
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| 2. |
- Fritioff, K, et al.
(författare)
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Single and double detachment from H-
- 2004
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622 .- 2469-9926 .- 2469-9934. ; 69:4, s. 042707-
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Tidskriftsartikel (refereegranskat)abstract
- Absolute cross sections for single and double detachment from H- following electron impact have been measured over a range of collision energies from the thresholds to 170 eV. The measurements were made using a magnetic storage ring. The ions in the ring were merged with a monoenergetic electron beam and neutral and positively charged fragments were detected. We cover larger energy ranges than in many of the previous experiments, and this is the first time both single and double detachment have been measured simultaneously. This allows us to present accurate ratios between the single and double detachment cross sections. On the basis of these ratio measurements we discuss possible mechanisms leading to double detachment.
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| 3. |
- Pal, S., et al.
(författare)
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Characteristics of potential fibre Bragg grating sensor-based devices at elevated temperatures
- 2003
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Ingår i: Measurement science and technology. - : IOP Publishing. - 0957-0233 .- 1361-6501. ; 14:7, s. 1131-1136
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Tidskriftsartikel (refereegranskat)abstract
- Fibre Bragg gratings (FBGs) of type I and IIA were fabricated in Ge-doped and B-Ge co-doped fibres using a 248 nm excimer laser and their performance characteristics were tested and compared with those of a chemical composition grating (CCG), written in a fluorine-germanium doped fibre, over a wide range of temperatures. Long-term testing (more than 600 h) involving a series of step-wise incremental temperature changes shows for the first time the potential of FBGs for high temperature measurement applications (up to and beyond 1100 degreesC), this depending on the type of FBG involved and the material and composition of the substrate fibre (the CCG was observed to be the most durable at very high temperatures). These gratings are likely to be useful for the simultaneous measurement of strain and temperature over these higher temperature ranges.
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