J. Äystö - Academia.edu (original) (raw)

Papers by J. Äystö

Indirect techniques have been used to obtain information about reaction rates for several proton ... more Indirect techniques have been used to obtain information about reaction rates for several proton capture reactions that occur on short-lived nuclei. The techniques used to carry out the measurements are reviewed and the results obtained are presented. Also future prospects for further measurements with a new facility, T-REX, are discussed.

Nuclear Physics A, 1982

Delayed charged particle emission associated with the precursor nuclide 40Sc was studied by use o... more Delayed charged particle emission associated with the precursor nuclide 40Sc was studied by use of the He-jet technique. Altogether 40 proton groups (1.0 MeV < Ep < 3.7 MeV) and 21 alpha-particle groups (2.0 MeV < Ealpha < 4.6 MeV) were observed. Total proton and alpha-particle branching ratios were measured to be (4.4+/-0.7) × 10-3 and (0.17+/-0.05) × 10-3, respectively. Association of the delayed particle emitting levels with the levels observed in resonance reaction studies is discussed. The fact that the most prominent alpha-particle groups do not have a counterpart in resonance reaction data suggests collectivity or a cluster configuration for the emitting levels. Log ft values (upper limits) for beta+ transitions to particle emitting levels were deduced from the measured absolute intensities of the proton and alpha-particle transitions. Beta strength function is qualitatively discussed in terms of a simple shell-model description.

AIP Conference Proceedings

In this contribution examples of the application of new technologies to disentangle the mechanism... more In this contribution examples of the application of new technologies to disentangle the mechanism of beta-delayed multi-particle emission are given. In particular the mechanism of beta-delayed two-proton emission from 31Ar is resolved and proved to be sequential, both for isospin allowed and isospin forbidden transitions. The analysis of the 9C decay has been focused in the study of the 12.2

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms

AIP Conference Proceedings, 2009

Using the Advanced Time-Delayed method we have studied transition rates in several neutron-rich n... more Using the Advanced Time-Delayed method we have studied transition rates in several neutron-rich nuclei at the magic shell closures. These include the heavy Co and Fe nuclei just below the Z = 28 shell closure at the point of transition from spherical to collective structures. Of particular interest is 63Fe located exactly at the point of transition at N = 37. A substantial increase in the information on this nucleus was obtained from a brief fast timing study conducted at ISOLDE. The new results indicate that 63Fe seems to depart from a simple shell model structure observed for heavier N = 37 isotones of 65Ni and 67Zn. Another region of interest are the heavy Cd and Sn nuclei at N = 72, 74 and the properties of negative parity quasi-particle excitations. These experiments, performed at the IGISOL separator at Jyväskylä, revealed interesting properties of the E2 rates in the sequence of E2 transitions connecting the 10+, 8+, 6+, 4+, 2+ and 0+ members of the multiplet of levels in 122Sn due to neutrons in the h11/2 orbit.

AIP Conference Proceedings, 2006

Nuclear structure effects probed by precision atomic mass measurements. [AIP Conference Proceedin... more Nuclear structure effects probed by precision atomic mass measurements. [AIP Conference Proceedings 831, 124 (2006)]. A. Jokinen, V.‐V. Elomaa, T. Eronen, U. Hager, J. Hakala, A. Kankainen, I. Moore, S. Rahaman, S. Rinta‐Antila, T. Sonoda, J. Äystö. Abstract. ...

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 1992

Exotic nuclei and atomic masses (ENAM 98), 1998

ABSTRACT Exotic neutron-rich fission products obtained from IGISOL on-line mass separator for mas... more ABSTRACT Exotic neutron-rich fission products obtained from IGISOL on-line mass separator for mass chain A=113 have been investigated by gammagamma coincidence and spectrum-multiscaling measurements. Gamma transitions following beta decay of Tc to Ru have been identified and a 0.5 s isomeric state in Ru has been found. Decay schemes of Ru and Rh isotopes have been considerably extended. Large feedings to high-lying levels in Rh lead to revision of the B(GT) strength.

Acta Physica Polonica Series B

ABSTRACT

Physical Review Letters, 2015

The 4th International Conference on Exotic Nuclei and Atomic Masses, 2005

ABSTRACT The main goal of the upgrade project of the IGISOL was to increase the yields of the mas... more ABSTRACT The main goal of the upgrade project of the IGISOL was to increase the yields of the mass-separated reaction products. The first tests showed that the goal was met. Typically, the yields normalized to the primary beam intensity are at least three times higher than before the upgrade. In addition, we have started a project to selectively laser ionize neutral atoms in the gas jet emerging from the ion guide and guide the photo-ions with a radiofrequency ion trap to the acceleration stage of the isotope separator.

$Research paper thumbnail of Beta decay of the proton-rich <math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><msub><mi>T</mi><mi>z</mi></msub><mo>=</mo><mo>−</mo><mn>1</mn><mi mathvariant="normal">/</mi><mn>2</mn></mrow><annotation encoding="application/x-tex">T_z = -1/2</annotation></semantics></math>Tz=−1/2 nucleus, <math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><msup><mrow></mrow><mn>71</mn></msup><mi>K</mi><mi>r</mi></mrow><annotation encoding="application/x-tex">^{71}Kr</annotation></semantics></math>71Kr$

Beta decay of the Tz = -1/2 nuclide 71Kr has been studied at the ISOLDE PSB Facility at CERN. 71K... more Beta decay of the Tz = -1/2 nuclide 71Kr has been studied at the ISOLDE PSB Facility at CERN. 71Kr ions were produced in spallation reactions in a Nb foil using the 1 GeV proton beam and studied by means of beta-delayed proton, beta- and gamma-ray spectroscopy. The half-life and the beta-decay energy of 71Kr were determined using the decay of protons and positrons. These results: T1/2 = 100 ± 3 ms and QEC = 10.14 ± 0.32 MeV and the first observation of the b-branch to the 207 keV level in 71Br makes the extension of the systematics of Gamow-Teller matrix elements of mirror nuclei up to A = 71 possible. Gamow-Teller strength of the same magnitude as that of the fp-shell mirror nuclei is observed for the ground state transition.

EPJ Web of Conferences, 2014

Physical review C: Nuclear physics, 1996

... JR Persson School of Physics and Space Research, University of Birmingham, Edgbaston, Birming... more ... JR Persson School of Physics and Space Research, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom A. Popov St. ... 6 K. Shizuma, H. Ahrens, JP Bocquet, N. Kaffrell, BD Kern, H. Lawin, RA Meyer, K. Sistemich, G. Tittel, and N. Traut-mann, Z. Phys. ...