I. Pohjalainen

Single and Double Beta-Decay Q Values among the Triplet ^{96}Zr, ^{96}Nb, and ^{96}Mo.

The atomic mass relations among the mass triplet ^{96}Zr, ^{96}Nb, and ^{96}Mo have been determined by means of high-precision mass measurements using the JYFLTRAP mass spectrometer at the IGISOL facility of the University of Jyväskylä. We report Q values for the ^{96}Zr single and double β decays to ^{96}Nb and ^{96}Mo, as well as the Q value for the ^{96}Nb single β decay to ^{96}Mo, which are Q_{β}(^{96}Zr)=163.96(13), Q_{ββ}(^{96}Zr)=3356.097(86), and Q_{β}(^{96}Nb)=3192.05(16)  keV. Of special importance is the ^{96}Zr single β-decay Q value, which has never been determined directly. The single β decay, whose main branch is fourfold unique forbidden, is an alternative decay path to the ^{96}Zr ββ decay, and its observation can provide one of the most direct tests of the neutrinoless ββ-decay nuclear-matrix-element calculations, as these can be simultaneously performed for both decay paths with no further assumptions. The theoretical single β-decay rate has been re-evaluated using a shell-model approach, which indicates a ^{96}Zr single β-decay lifetime within reach of an experimental verification. The uniqueness of the decay also makes such an experiment interesting for an investigation into the origin of the quenching of the axial-vector coupling constant g_{A}.

High-resolution laser spectroscopy of long-lived plutonium isotopes

Long-lived isotopes of plutonium were studied using two complementary techniques, high-resolution resonance ionisation spectroscopy (HR-RIS) and collinear laser spectroscopy (CLS). Isotope shifts have been measured on the

Development of a low-energy radioactive ion beam facility for the MARA separator

5f^67s^2\ ^7F_0 \rightarrow 5f^56d^27s\ (J=1)

Characterization and performance of the DTAS detector

and

Experimental study of 100Tc β decay with total absorption γ-ray spectroscopy

5f^67s^2\ ^7F_1 \rightarrow 5f^67s7p\ (J=2)

Study of the

atomic transitions using the HR-RIS method and the hyperfine factors have been extracted for the odd mass nuclei

\beta

^{239,241}

-decay of

Pu. Collinear laser spectroscopy was performed on the

^{100}

5f^67s\ ^8F_{1/2} \rightarrow J=1/2\; (27523.61\text{cm}^{-1})

Tc with Total Absorption

ionic transition with the hyperfine