| 1. |
- Elekes, Z., et al.
(author)
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Shape coexistence in 66Se
- 2023
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In: Physics Letters B. - : Elsevier. - 0370-2693 .- 1873-2445. ; 844
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Journal article (peer-reviewed)abstract
- The nuclear structure of 66Se, nucleus beyond the N=Z line on the proton-rich side of the valley of stability, was investigated by the neutron knock-out reaction 67Se(12C,X)66Se using a 12C target. The analysis of the singles spectrum of the γ-rays emitted during the de-excitation of the populated low-lying excited states revealed two previously detected (927(4) keV, 1460(32) keV) and three new (744(6) keV, 1210(17) keV, 1661(23) keV) transitions. The 744-keV, the 1210-keV, and the 1460-keV transitions were found to be in coincidence with the one at 927 keV. The spectrum coincident with the 927-keV transition showed a further possible transition at 299(35) keV, which was obscured by significant atomic background in the singles spectrum. This transition might correspond to a peak previously reported at 273(5) keV that could not be assigned to 66Se unambiguously. Based on a comparison of the experimental data to theoretical calculations, four new excited states are proposed which suggest that 66Se exhibits shape coexistence.
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| 2. |
- Kirsebom, O. S., et al.
(author)
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Precise and accurate determination of the B-8 decay spectrum
- 2011
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In: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993. ; 83:6
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Journal article (peer-reviewed)abstract
- Accurate measurements of the B-8 neutrino spectrum are important for the interpretation of solar neutrino data. Experimentally, the B-8 neutrino spectrum can be obtained from the measurement of the beta-delayed alpha spectrum. We report on an alpha-alpha coincidence measurement performed at the IGISOL facility in Jyvaskyla, Finland. Our measurement allows extensive cross-checks to be performed and gives a more intense neutrino spectrum at high energies compared to the present standard. The deviation reaches 4% at the end point of the spectrum. Below 11 MeV, the deviation is less than 1%.
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| 3. |
- Saastamoinen, T., et al.
(author)
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Electromagnetic coherence theory of laser resonator modes
- 2005
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In: Journal of the Optical Society of America a-Optics Image Science and Vision. - 1084-7529. ; 22:1, s. 103-108
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Journal article (peer-reviewed)abstract
- A theory of open laser resonators is formulated within the framework of the electromagnetic coherence theory. It is shown that if only one Fox-Li mode contributes to the field at a given frequency. then the field at that frequency is necessarily completely coherent in view of the space- frequency, counterpart of the recently introduced degree of coherence of electromagnetic fields [Opt. Express 11, 1137 (2003)]. It is also shown that the relation between the number of Fox-Li modes and the new degree of coherence is analogous to the relation established in the scalar theory of laser resonator modes. Difficulties that arise with the formerly introduced visibility-based definition of the electromagnetic degree of coherence are briefly discussed.
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| 4. |
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| 5. |
- Smith, D. L., et al.
(author)
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Lifetime measurements of the negative-parity 7(-) and 8(-) states in Cd-122
- 2008
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In: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 77:1, s. 014309-
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Journal article (peer-reviewed)abstract
- The Advanced Time-Delayed beta gamma gamma(t) method was used to measure lifetimes of selected high-spin states in Cd-122 populated from beta(-) decay of the J(pi)=(9(-)) isomer in Ag-122. From the gamma gamma coincidences, a new energy level was established at 2616.6 keV with a suggested spin-parity assignment of 8(-). Lifetimes were determined for the high-spin states at 2616.6 and 2502.7 keV as T-1/2=1.35(29) ns and 0.24(6) ns, respectively. The transition rates for gamma rays de-exciting the 7(-) states in the N=74 isotones of Cd-122, Sn-124, and Te-126 were found to be very similar.
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| 6. |
- Tervo, J., et al.
(author)
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Degree of coherence and electromagnetic resonators
- 2004
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In: PHOTON MANAGEMENT. - : SPIE. - 0819453838 ; , s. 28-35
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Conference paper (peer-reviewed)abstract
- Electromagnetic theory of open laser resonators is formulated in the domain of partially coherent optics. The theory is then used to find out the electromagnetic degree of coherence of the field in various situations. It is shown that if only one transverse mode is present in the steady-state condition, then the field is necessarily completely coherent in view of the recently introduced degree of coherence for electromagnetic fields [Opt. Express. 11, 1137 (2003)].
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| 7. |
- Daniel, Salman, et al.
(author)
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Dynamic control of optical transmission through a nano-slit using surface plasmons
- 2015
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In: Optics Express. - : Optica Publishing Group. - 1094-4087. ; 23:17, s. 22512-22519
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Journal article (peer-reviewed)abstract
- We demonstrate how the optical transmission by a directly illuminated, sub-wavelength slit in a metal film can be dynamically controlled by varying the incident beam's phase relative to that of a stream of surface plasmon polaritions which are generated at a nearby grating. The transmission can be smoothly altered from its maximum value to practically zero. The results from a simple model and from rigorous numerical simulations are in excellent agreement with our experimental results. Our method may be applied in all-optical switching.
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| 8. |
- Koldste, G. T., et al.
(author)
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Multiparticle emission in the decay of Ar-31
- 2014
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In: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993. ; 89:6
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Journal article (peer-reviewed)abstract
- A multihit capacity setup was used to study the decay of the dripline nucleus Ar-31, produced at the ISOLDE facility at CERN. A spectroscopic analysis of the beta-delayed three-proton decay of Ar-31 is presented for the first time together with a quantitative analysis of the beta-delayed 2p gamma decay. A new method for determination of the spin of low-lying levels in the beta p daughter 30S using proton-proton angular correlations is presented and used to determine that the spin of the 5.2-MeV level is most likely 3(+) with 4(+) also possible. The half-life of Ar-31 is found to be 15.1(3) ms. An improved analysis of the Fermi beta strength including the beta 3p-decay mode gives a total measured branching ratio of 3.60(44)%, which is lower than the theoretical value found to be 4.24(43)%. Finally, a previously unidentified. transition from the isobaric analog state in the decay of Ar-33 has been found.
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| 9. |
- Koldste, G. T., et al.
(author)
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Relative proton and gamma widths of astrophysically important states in S-30 studied in the beta-delayed decay of Ar-31
- 2013
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In: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993. ; 87:5
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Journal article (peer-reviewed)abstract
- Resonances just above the proton threshold in S-30 affect the P-29(p, gamma)S-30 reaction under astrophysical conditions. The (p,gamma)-reaction rate is currently determined indirectly and depends on the properties of the relevant resonances. We present here a method for finding the ratio between the proton and gamma partial widths of resonances in S-30. The widths are determined from the beta 2p- and beta p gamma-decay of Ar-31, which is produced at the ISOLDE radioactive ion beam facility at the European research organization CERN. Experimental limits on the ratio between the proton and gamma partial widths for astrophysical relevant levels in S-30 have been found for the first time. A level at 4689.2(24) keV is identified in the gamma spectrum, and an upper limit on the Gamma(p)/ Gamma gamma ratio of 0.26 (95% C.L.) is found. In the two-proton spectrum two levels at 5227(3) keV and 5847(4) keV are identified. These levels were previously seen to gamma decay and upper limits on the Gamma(gamma)/Gamma(p) ratio of 0.5 and 9, respectively, (95% C.L.) are found, where the latter differs from previous calculations.
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| 10. |
- Koldste, G. T., et al.
(author)
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Sizeable beta-strength in Ar-31 (beta 3p) decay
- 2014
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In: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 737, s. 383-387
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Journal article (peer-reviewed)abstract
- We present for the first time precise spectroscopic information on the recently discovered decay mode beta-delayed 3p-emission. The detection of the 3p events gives an increased sensitivity to the high energy part of the Gamow-Teller strength distribution from the decay of Ar-31 revealing that as much as 30% of the strength resides in the beta 3p-decaymode. A simplified description of how the main decay modes evolve as the excitation energy increases in Cl-31 is provided.
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