H. Kettunen

A triplet of differently shaped spin-zero states in the atomic nucleus 186 Pb

Understanding the fundamental excitations of many-fermion systems is of significant current interest. In atomic nuclei with even numbers of neutrons and protons, the low-lying excitation spectrum is generally formed by nucleon pair breaking and nuclear vibrations or rotations. However, for certain numbers of protons and neutrons, a subtle rearrangement of only a few nucleons among the orbitals at the Fermi surface can result in a different elementary mode: a macroscopic shape change. The first experimental evidence for this phenomenon came from the observation of shape coexistence in 16O (ref. 4). Other unexpected examples came with the discovery of fission isomers and superdeformed nuclei. Here we find experimentally that the lowest three states in the energy spectrum of the neutron deficient nucleus 186Pb are spherical, oblate and prolate. The states are populated by the α-decay of a parent nucleus; to identify them, we combine knowledge of the particular features of this decay with sensitive measurement techniques (a highly efficient velocity filter with strong background reduction, and an extremely selective recoil-α-electron coincidence tagging method). The existence of this apparently unique shape triplet is permitted only by the specific conditions that are met around this particular nucleus.

The GREAT spectrometer

Abstract The GREAT spectrometer is designed to measure the decay properties of reaction products transported to the focal plane of a recoil separator. GREAT comprises a system of silicon, germanium and gas detectors optimised for detecting the arrival of the reaction products and correlating with any subsequent radioactive decay involving the emission of protons, α particles, β particles, γ rays, X-rays or conversion electrons. GREAT can either be employed as a sensitive stand-alone device for decay measurements at the focal plane, or used to provide a selective tag for prompt conversion electrons or γ rays measured with arrays of detectors deployed at the target position. A new concept of triggerless data acquisition (total data readout) has also been developed as part of the GREAT project, which circumvents the problems and limitations of common dead time in conventional data acquisition systems.

From the Reference SEU Monitor to the Technology Demonstration Module On-Board PROBA-II

The reference SEU Monitor system designed and presented in 2005 (R. H. SOslashrensen, F.-X. Guerre, and A. Roseng ldquoDesign, testing and calibration of a reference SEU monitor system,rdquo in Proc. RADECS, 2005, pp. B3-1-B3-7) has now been used by many researchers at many radiation test sites and has provided valuable calibration data in support of numerous projects. As some of these findings and results give new insight into improved inter-facility calibrations and provide additional inputs into ongoing SEE research, a few of the more interesting cases are presented. Furthermore the dasiadetector elementpsila, the Atmel AT60142F SRAM, now in a hybrid configuration, will form the key detector element in the Technology Demonstration Module (TDM) to be flown on-board the PROBA-II satellite, to be launched at the beginning of 2009. This flight opportunity extends the Reference SEU Database with both ground and space data, taken on the same device under identical operating conditions. Additionally, the Reference SEU Monitor concept is employed as the basis for the new Reference SEL Monitor system, currently under characterization and preparation for integration on the TDM. Ground SEU/SEL characterization of this latch-up experiment is also presented as well as the basic concept of the TDM, the PROBA-II Radiation Monitor module.

α decay studies of the nuclides U 218 and U 219

Very neutron deficient uranium isotopes were produced in fusion evaporation reactions using

Linear Energy Transfer of Heavy Ions in Silicon

^{40}\mathrm{Ar}

Upgrades for the RADEF Facility

ions on

Energy loss measurement of protons in liquid water

^{182}\mathrm{W}

Decay studies of Au 170 , 171 , Hg 171 – 173 , and Tl 176

targets. The gas-filled recoil separator RITU was employed to collect the fusion products and to separate them from the scattered beam and other reaction products. The activities were implanted into a position sensitive silicon detector after passing through a gas-counter system. The isotopes were identified using spatial and time correlations between the implants and the decays. Two

Heavy Ion Sensitivity of 16/32-Gbit NAND-Flash and 4-Gbit DDR3 SDRAM

\ensuremath{\alpha}

Ultra-high resolution mass separator—Application to detection of nuclear weapons tests

-decaying states, with