Angular distribution of photons from the delay of the GDR in hot and rotating light Yb nuclei from exclusive experiments

Abstract Angular distributions of photons associated with the damping of excited-state giant dipole resonances (GDR) in hot and rotating 161,162 Yb nuclei have been measured in exclusive experiments using the HECTOR array. In reactions with heavy ions ( 48 T) angular distributions are determined as a function of the angular momentum of the compound nuclei. In reactions with lighter ions ( 17,18 O) a difference method is applied to isolate GDR decays originating from specific excitation regions. The systematics of the measured angular distributions as a function of excitation energy and angular momentum are compared to theories taking into account fluctuations of the shape and orientation of the excited nuclei

The rotational γ-continuum in the mass region A≈110

Abstract Unresolved γ transitions of 114 Te and of 112 Sn sorted into one-dimensional and two-dimensional spectra have been studied. The reaction 64 Ni + 54 Cr at bombarding energies 230, 240, 250, 260, 270 MeV was used and the γ -rays were detected with the EUROBALL array. In the case of the nucleus 114 Te the values of the multiplicity as a function of bombarding energy and of the moment of inertia were obtained. The effective moment of inertia was found to be almost constant in the interval I=20 – 40 ℏ , in contrast to the decreasing behaviour of the dynamic moment of inertia for the terminating yrast band. The ridge valley structures in E γ 1 ×E γ 2 spectra of 114 Te and of 112 Sn were analysed with the fluctuation analysis technique. The analysis of the two nuclei are compared to simulations based on microscopic cranking calculations with residual interactions included. A rather good agreement is found between data and predictions

Effect of E1 decay in the population of superdeformed structures

Abstract Spectra of the yrast and excited superdeformed bands, forming the E2 quasi-continuum, are measured with the EUROBALL array for the nucleus 143 Eu, in coincidence with high-energy γ-rays (Eγ>3 MeV). It is found that the intensity population of the superdeformed states is enhanced by a factor of ≈1.6 when a coincidence with a γ-ray with energy >6 MeV is required, in reasonable agreement with the increase of the line shape of the Giant Dipole Resonance built on a superdeformed configuration. This result shows that when an high energy E1 γ-ray is involved in the decay it is more likely connected with a SD rather than a ND nucleus. In addition, the analysis of the rotational quasi-continuum suggests the presence of a superdeformed component. The data are also compared and found consistent with simulation calculations of the relative intensities of the SD states, including the E1 decay of superdeformed nature

Detection properties and internal activity of newly developed La-containing scintillator crystals

International audienceIn this work, we will present the characterization, in terms of gamma response and internal activity of newly developed crystals that contains Lanthanum in their chemical formula. In particular we tested two LaBr 3 :Ce,Sr, one CLLBC and two CLLB crystals with different volumes. These crystals just overcome the prototype stage and, even if the production in still not standardized at least for large optics, they have been very recently commercialized in sizes interesting for high-energy gamma-ray spectroscopy, as for application in nuclear physics experiments. In particular, we will report on the study of the decay time, light yield and energy resolution with gamma rays, on the response as a function of the gamma interaction point and on the internal activity due to the presence of Lanthanum

3\u2033 7 3\u2033 LaBr3:Ce position sensitivity with multi-anode PMT readout

The response of a cylindrical continuous 3\u2033 7 3\u2033 LaBr3:Ce crystal coupled to four Position Sensitive photomultipliers (PSPMT) was studied using a 1 mm collimated beam of 662 keV gamma rays

Performances of a 1\u2033 71\u2033 Cs2LiYCl6 scintillator detector

In this work we have measured the performances of a 1\u2033 71\u2033 sample of a CLYC scintillator (Cs2LiYCl6) with 95% enrichment of 6Li produced by RMD. Different PMT models, with borosilicate glass window or quartz window have been used. The Pulse line-shape and Pulse shape discrimination for different type of incident radiation (gamma-rays and thermal neutrons) have been investigated. The response to thermal neutrons has been measured using an AmBe source and a digital oscilloscope. A measurement of the internal radiation and the energy resolution for different gamma rays have been additionally performed

Performances of a 1 '' x1 '' Cs2LiYCl6 scintillator detector

In this work we have measured the performances of a 1″×1″ sample of a CLYC scintillator (Cs 2 LiYCl 6 ) with 95% enrichment of 6 Li produced by RMD. Different PMT models, with borosilicate glass window or quartz window have been used. The Pulse line-shape and Pulse shape discrimination for different type of incident radiation (gamma-rays and thermal neutrons) have been investigated. The response to thermal neutrons has been measured using an AmBe source and a digital oscilloscope. A measurement of the internal radiation and the energy resolution for different gamma rays have been additionally performed. © 2013 IEEE.status: publishe