Fast-timing measurements in neutron-rich odd-mass zirconium isotopes using LaBr3:Ce detectors coupled with Gammasphere

A fast-timing experiment was performed at the Argonne National Laboratory to measure the lifetimes of the lowest lying states of nuclei belonging to the deformed regions around mass number A 110 and A 150. These regions were populated via spontaneous fission of 252 Cf and the gamma radiation following the decay of excited states in the fission fragments was measured using 51 Gammasphere detectors coupled with 25 LaBr 3 :Ce detectors. A brief description of the acquisition system and some preliminary results from the fast-timing analysis of the fission fragment 100Zr are presented. The lifetime value of \u3c4 = 840(65) ps was found for the 2 + state in 100 Zr consistent within one standard deviation of the adopted value with 791 +26 -35 ps. This is associated with a quadrupole deformation parameter of 0.36(2) which is within one standard deviation of the literature value of 0.3556 +82 -57

Fast-timing measurements in the ground-state band of Pd114

Using a hybrid Gammasphere array coupled to 25 LaBr3(Ce) detectors, the lifetimes of the first three levels of the yrast band in Pd-114, populated via Cf-252 decay, have been measured. The measured lifetimes are tau(2+) = 103(10) ps, tau(4+) = 22(13) ps, and tau(6+) <= 10 ps for the 2(1)(+), 4(1)(+), and 6(1)(+) levels, respectively. Palladium-114 was predicted to be the most deformed isotope of its isotopic chain, and spectroscopic studies have suggested it might also be a candidate nucleus for low-spin stable triaxiality. From the lifetimes measured in this work, reduced transition probabilities B(E2; J -> J - 2) are calculated and compared with interacting boson model, projected shell model, and collective model calculations from the literature. The experimental ratio R-B(E2) = B(E2; 4(1)(+) -> 2(1)(+))/B(E2; 2(1)(+) -> 0(1)(+)) = 0.80(42) is measured for the first time in Pd-114 and compared with the known values R-B(E2) in the palladium isotopic chain: the systematics suggest that, for N = 68, a transition from gamma-unstable to a more rigid gamma-deformed nuclear shape occurs

Fast-timing measurements in the ground-state band of Pd 114

Using a hybrid Gammasphere array coupled to 25 LaBr3(Ce) detectors, the lifetimes of the first three levels of the yrast band in Pd114, populated via Cf252 decay, have been measured. The measured lifetimes are τ2+=103(10)ps, τ4+=22(13)ps, and τ6+≤10ps for the 21+, 41+, and 61+ levels, respectively. Palladium-114 was predicted to be the most deformed isotope of its isotopic chain, and spectroscopic studies have suggested it might also be a candidate nucleus for low-spin stable triaxiality. From the lifetimes measured in this work, reduced transition probabilities B(E2;J→J-2) are calculated and compared with interacting boson model, projected shell model, and collective model calculations from the literature. The experimental ratio RB(E2)=B(E2;41+→21+)/B(E2;21+→01+)=0.80(42) is measured for the first time in Pd114 and compared with the known values RB(E2) in the palladium isotopic chain: the systematics suggest that, for N=68, a transition from γ-unstable to a more rigid γ-deformed nuclear shape occurs

Fast-Timing measurements in 100zr using labr3(ce) detectors coupled with gammasphere

In order to investigate the evolution of nuclear deformation in the region of the chart of nuclides around mass numbers A ' 110 and A ' 150, an experiment was performed at the Argonne National Laboratory where the gamma-decay radiation emitted from the fission fragments of 252Cf was measured using 51 Gammasphere detectors coupled with 25 LaBr3(Ce) detectors. In this work, a short description of the experimental setup is presented together with some preliminary results from the fast-Timing analysis of the 4+ state of the nucleus 100Zr. A lifetime value of τ = 50(28) ps was obtained using the Generalized Centroid Shift Method. This result agrees with the literature value of τ = 53(4) ps within one standard deviation

Fast timing measurement using an labr3(Ce) scintillator detector array coupled with gammasphere

A fast-timing experiment was performed at the Argonne National Laboratory in December 2015 and January 2016, measuring decay radiation of fission products from a 252Cf fission source. Details of the set-up, integration with Digital Gammasphere, and the data acquisition system are presented. The timing performance of the set-up, capable of measuring lifetimes from the nanosecond region down to tens of picoseconds, is discussed. First preliminary results from the fast-timing analysis of the fission fragment data are presented

Fast timing measurement using an labr3(Ce) scintillator detector array coupled with gammasphere

A fast-timing experiment was performed at the Argonne National Laboratory in December 2015 and January 2016, measuring decay radiation of fission products from a252Cf fission source. Details of the set-up, integration with Digital Gammasphere, and the data acquisition system are presented. The timing performance of the set-up, capable of measuring lifetimes from the nanosecond region down to tens of picoseconds, is discussed. First preliminary results from the fast-timing analysis of the fission fragment data are presented

Immunochemical detection of arylamine N-acetyltransferase during mouse embryonic development and in adult mouse brain

Arylamine N-acetyltransferases (NATs) are important in susceptibility to xenobiotic-induced disorders (e.g., drug-induced autoimmune disease, bladder cancer), but their role in endogenous metabolism is yet to be elucidated. The discovery that human NAT1 acts upon p-aminobenzoylgluatamate (p-ABG) to generate p-acetamidobenzoylglutamate (p-AABG), a major urinary metabolite of folic acid, suggests that human NAT1 may play a role in folic acid metabolism and hence in the normal development of the neural tube. In this study we examined the distribution of NAT in neuronal tissue from adult mice and embryos. Immunohistochemical staining of the adult mouse cerebellum revealed NAT2 (the mouse homologue of human NAT1) expression in the cell bodies and dendrites of Purkinje cells and in the neuroglia of the molecular layer. In embryos, NAT2 was detected in developing neuronal tissue on days 9.5, 11.5, and 13.5. It was expressed intensely in the neural tube around the time of closure. The level of expression subsequently declined in the neuroepithelium but increased in glial cells. In addition, NAT2 was detected in the developing heart and gut. These findings demonstrate that the embryo itself expresses an enzyme which is involved in the metabolism of folic acid, so that the role played by both mother and embryo must be considered when examining the role of folic acid in embryonic development. These findings imply that polymorphisms in NAT genes could play a role in determining susceptibility to neural tube defects (NTD) and orofacial clefting, developmental disorders which can be prevented by dietary administration of folic acid.</p