Characterization of PARIS LaBr₃(Ce)-NaI(Tl) phoswich detectors up toE_γ∼ 22 MeV

Abstract

In order to understand the performance of the PARIS (Photon Array for the studies with Radioactive Ion and Stable beams) detector, detailed characterization of two individual phoswich (LaBr 3 (Ce)-NaI(Tl)) elements has been carried out. The detector response is investigated over a wide range of E γ = 0.6 to 22.6 MeV using radioactive sources and employing 11 B(p, γ) reaction at E p = 163 keV and E p = 7.2 MeV. The linearity of energy response of the LaBr 3 (Ce) detector is tested upto 22.6 MeV using three different voltage dividers. The data acquisition system using CAEN digitizers is set up and optimized to get the best energy and time resolution. The energy resolution of ∼ 2.1% at E γ = 22.6 MeV is measured for the configuration giving best linearity upto high energy. Time resolution of the phoswich detector is measured with a 60 Co source after implementing CFD algorithm for the digitized pulses and is found to be excellent (FWHM ∼ 315 ps). In order to study the effect of count rate on detectors, the centroid position and width of the E γ = 835 keV peak were measured upto 220 kHz count rate. The measured efficiency data with radioactive sources are in good agreement with GEANT4 based simulations. The total energy spectrum after the add-back of energy signals in phoswich components is also presented.

The GALILEO γ-ray array at the Legnaro National Laboratories

“…This read-out was also tested with fast-responding scintillators, e.g. PARIS [42,43] and FATIMA [44,45] for which time resolution of ∼250 ps is obtained using the V1730 digitizers [46].…”

Neutron Response of PARIS Phoswich Detector

“…Each element is made up of 2 ′′ × 2 ′′ ×2 ′′ LaBr 3 (Ce) crystal optically coupled to a 2 ′′ × 2 ′′ ×6 ′′ NaI(Tl) crystal followed by a single PMT for signal readout. Recently, two PARIS phoswich detector element have been characterized over a wide range of γ-ray energies [8]. In the high energy γ-ray measurement, the evaporated neutrons are the major sources of contamination, which can be rejected by time-of-flight (TOF) technique.…”

First evidence for non 1− pygmy dipole resonance in neutron-rich nuclei

“…It was proved to be more dependent on the detailed properties of the nuclear force than the IVGDR [15][16][17][18]. Additional experimental information is helpful in this regard such as the observation of a new decay mode in 142 Nd [19], 60 Ni [20], 130 Te [21] and 140 Ce [22] which can provide complementary information on the wave functions of these states. It revealed that the levels associated with PDR have a regular behavior: ∼25% of them decay to excited states.…”