Speaker
Description
The study of β-decays far from stability is essential to understand the evolution of nuclear
structure and nucleosynthesis processes. β-decay experiments with such exotic nuclei involve
intense cocktail beams from fragmentation facilities. The role of an implantation detector in
these experiments is to measure the energy and the positions of both heavy ion implantation
and β-ray emission to correlate the identified ion with β-decay events.
Due to the lack of time resolution of conventional Silicon strip detectors, we have developed
a new implantation detector using a segmented YSO (Yttrium Orthosilicate) scintillator array
for time-of-flight spectroscopy of the β-delayed neutron emission. The new detector was
implemented in β-delayed neutron measurement experiments at RIKEN RI Beam Factory,
and it was confirmed that the YSO detector correlates β and implant events better due to its
higher effective atomic number Z~35.
The success of the YSO detector motivated us to develop a new detector using heavier
scintillator material. We will report on the design of the new detector using
(Gd,139La)2Si2O7:Ce (A=139 enriched La-GPS) crystal which has a much higher effective
atomic number (Z~51) and is expected to have better β-implant efficiency with a lower
background.
