J. Honkanen

The ion guide isotope separator on-line, IGISOL

Abstract A new ISOL method, the IGISOL (Ion Guide Isotope Separator On-Line), permits thermalized primary recoil ions produced in nuclear reactions to be run directly through a mass separator without a conventional ion source. It allows a fast (≳ 100 μs) separation of various radioactive isotopes of both volatile and nonvolatile elements. The overall separation efficiencies measured for heavy nuclides produced in light ion induced reactions are up to 10%. The shortest-lived activity identified in an on-line separation is the 182 μs isomeric state of 207Bi.

Ion guide method for on-line isotope separation

Abstract A new ISOL technique, the ion guide method for isotope separation, has been developed. The method is based on thermalization of primary recoil ions from nuclear reactions in helium and on their transfer by helium flow through a differential pumping system into the accelerating stage of an isotope separator. With this approach, separation times in the submillisecond region are achievable for all elements. The ion guide has no ionizer but instead exploits charge exchange mechanisms related to nuclear reactions and recoil thermalization processes. Operation takes place at room temperature and the simple construction involves no components that can wear out. These properties ensure smooth and stable operating conditions. The overall separation efficiencies measured for heavy nuclides produced by light-ion reactions are up to 10%. The shortest-lived activity identified in an on-line separation is the 182-μs isomeric state of 207Bi. The production rate of the mass separated 440-μs isomeric state of 43Sc is ≈ 2 × 103 ions/μC.

Levels in 110Pd, 112Pd, 114Pd and 116Pd from the beta decays of the on-line mass separated Rh isotopes☆

Abstract The energy levels of even 110–116 pd nuclei have been studied from β-decays of odd-odd 110–116 Rh isotopes produced at the on-line isotope separator IGISOL. Two β-decaying states with I π = 1 + and I ⩾4 have been identified in all the cases. New level schemes with preliminary spin assignments have been constructed for 112 Pd, 114 Pd and 116 Pd. Similarities with the level structures of their Xe isotones have been pointed out.

Decay of 24Al and 24Alm to γ-Ray and α-Particle Emitting States in 24Mg

The level structure of 24Mg and decay properties of 129 ms 24Alm and 2.07 s 24Al have been investigated by means of γ-ray and particle spectroscopy. The energy and intensity of the isomeric transition were measured to be 425.8 ± 0.1 keV and (82.5 ± 3.0)%, respectively. The isomer was observed to decay via a super-allowed transition with a log ft value of 3.51 ± 0.04 to its 1+, 9965.2 ± 1.5 keV analog state in 24Mg. In addition, decay to seven particle-emitting levels and four levels depopulated by γ-ray emission were observed. In the decay of 2.07 s 24Al a new delayed α-particle group with an energy 3.04 MeV and three new γ-transitions were observed. More accurate values than those reported in earlier studies are given for γ-ray energies and intensities, and also for deduced excitation energies in 24Mg. Particle branches (per disintegration) were measured for the observed delayed particle groups.

Delayed particle emission following the β+ decay of 28P and 32Cl

Abstract Thin sources of 28 P and 32 Cl were prepared by depositing recoil atoms from the reactions 28 Si(p, n) 28 P and 32 S(p, n) 32 Cl with a helium jet onto a fast transport tape. Delayed particle spectra were measured with high resolution using Si(Au) surface barrier detectors. Six proton groups and ten α-particle groups in the energy ranges 0.4 MeV E p E α 28 P. Six proton groups and eleven α-particle groups in the energy ranges 0.7 MeV E p E α 32 Cl. Absolute intensities of the individual proton and α-particle transitions were determined and corresponding upper limits for the log ft values of the precursor β + transitions were calculated. The total proton and α-particle branching ratios are 1.3 × 10 −5 and 8.6 × 10 −6 for 28 P and 2.6 × 10 −4 and 5.4 × 10 −4 for 32 Cl, respectively. The observed particle groups were assigned to excited levels known from resonance reaction studies in 28 Si and 32 S. Ratios of the partial widths for α-particle and proton emission, Γ α /Γ p were determined for four levels in 28 Si and for one level in 32 S; upper limits are given for several other levels. New evidence for spin-parity assignments is discussed. Partial decay schemes are presented for 28 P and 32 Cl.

Beta-decay properties of 25 Si and 26 P

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Identification and decay of new neutron-rich isotopes 115Rh and 116Rh

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Separation of fission products by the ion guide fed isotope separator, IGISOL

-decay properties of the neutron-deficient nuclei 25Si and 26P have been investigated at the GANIL/LISE3 facility by means of charged-particle and

Beta decay and delayed proton emission of a new nuclide 59Zn

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Experimental and Shell-Model Study of the Beta Decay of 43Ti

-ray spectroscopy. The decay schemes obtained and the Gamow-Teller strength distributions are compared to shell-model calculations based on the USD interaction. B(GT) values derived from the absolute measurement of the