FATIMA — FAst TIMing Array for DESPEC at FAIR

Abstract

The components, working principle and characteristics of FATIMA (FAst TIMing Array), a fast-timing detector system for DESPEC at FAIR, are described. The core system includes 36 LaBr 3 (Ce) scintillator detectors, a mounting frame for the DESPEC station and a VME-based fast-timing data acquisition system. The current electronic timing circuit is based on V812 constant fraction discriminators and V1290 time-to-digital converters. Gamma-ray energies are measured using V1751 digitisers. Characteristics of the core FATIMA system including efficiency, energy, and coincidence resolving time, as well as limitations, are discussed on the basis of test measurements performed in the S4 cave at GSI, Germany. The coincidence -time resolution for the prompt 60 Co cascade is determined to be ∼320 ps full width at half maximum. The total full energy peak efficiency at 1 MeV for the 36 detector array in the DESPEC setup is 2.9%. The energy-dependent prompt response centroid curve with the current CFD/TDC combination is shown to be smooth; the centroid shift method can be applied for the measurement of half-lives below 200 ps. An overview of applications of the FATIMA detectors as an ancilliary system in combination with other detector arrays during recent years is given. Data on the operation of the detectors in the presence of magnetic fields are presented.

Gamma spectroscopy with AGATA in its first phases: New insights in nuclear excitations along the nuclear chart

“…AGATA 1π coupled to the VAMOS++ spectrometer in vacuum mode enabled the γ -ray spectroscopy up to medium spins in nuclei populated with fusion-fission or multi-nucleon transfer reactions. The detection systems of LaBr 3 scintillators, FATIMA [59][60][61] and PARIS [62] were installed to improve the γ -ray detection efficiency for rare event studies. With the PARIS clusters γ -rays were measured up to high energy with a good timing feature, while the FATIMA array allowed measurements of lifetimes in pico-nano second range.…”

“…The more recent experiment performed with AGATA at GANIL provided values of the B(E2) for the 11/2 − → 7/2 − transition in 61,63 Co [164]. These nuclei were populated in multi-nucleon transfer reactions from a 6.5 AMeV 238 U beam impinging on a 64 Ni target.…”

“…As reported in [165,166] and [167] and the 9/2 + states was investigated in a chain of Cu isotopes to search for couplings to the octupole vibration of the Ni core. In particular, lifetimes for the nuclei 61,65,67 Cu and the corresponding B(E3) were interpreted as due to the coupling of the ground-state proton in p 3/2 orbital to the 3 − phonon of the Ni core (Z = 28). The levels involved in these couplings are shown in the left panels of Fig.…”

“…The measured B(E3) values for the 9/2 + → 3/2 − transitions in 61,65,67 Cu, as deduced from lifetimes measurements using both the plunger device and the fast timing techniques, are shown in right panel of Fig. 38.…”

Observation of new neutron-rich isotopes in the vicinity of Zr110

“…In the present paper, we report for the first time the measurement and identification of the most neutron-rich isotopes of the elements from bromine (atomic number Z = 35) to niobium (Z = 41). The radionuclides of interest were produced in an experiment aimed at the study of the radioactive decay properties of neutron-rich nuclei in the A ≈ 110 region at the RIKEN Radioactive Isotope Beam Factory (RIBF), in which the EUroball RIKEN Cluster Array (EURICA) and a fast-timing array of LaBr 3 (Ce) detectors (FATIMA) were used for γ -ray detection [22,23]. Some results from this experiment were published in Refs.…”