Investigating timing properties of modern digitizers utilizing interpolating CFD algorithms and the application to digital fast-timing lifetime measurement

The performance of two implementations of digital real-time interpolating constant fraction discriminator algorithms with respect to fast-timing lifetime measurements are investigated. The implementations integrated in two different digitizers were evaluated in terms of the effects of tuning parameters of the digital CFDs and the influence of different input amplitudes on the time resolution and time walk characteristics. Reference is made to the existing analog standard of fast-timing techniques. The study shows, that the timing performance of both modules is comparable to established fast-timing setups using analog constant fraction discriminators, but with the added benefit of digital processing. Both digitizer modules were found to be highly effective and user-friendly instruments for modern fast-timing requirements.Comment: 13 pages, 16 figure

Lifetime measurements of the low-lying excited states of ²⁰⁸Po

In this study we present the preliminary results about the lifetimes of the 2₂⁺, 4₁⁺ states of ²⁰⁸Po and the upper limit of the lifetime of the 2₁⁺ state. For measuring the lifetimes of the 2₁⁺ and 4₁⁺ states the Recoil Distance Doppler Shift (RDDS) method and for the lifetime of the 2₂⁺ state the Doppler Shift Attenuation method (DSAM) were used. The resulting absolute transition strength B(M1 ; 2₂⁺ → 2₁⁺) ≥ 0.122(20) μN² reveals the predominant isovector nature of the 2₂⁺ state of ²⁰⁸Po

Lifetime measurements of the low-lying excited states of ²⁰⁸Po

In this study we present the preliminary results about the lifetimes of the 2₂⁺, 4₁⁺ states of ²⁰⁸Po and the upper limit of the lifetime of the 2₁⁺ state. For measuring the lifetimes of the 2₁⁺ and 4₁⁺ states the Recoil Distance Doppler Shift (RDDS) method and for the lifetime of the 2₂⁺ state the Doppler Shift Attenuation method (DSAM) were used. The resulting absolute transition strength B(M1 ; 2₂⁺ → 2₁⁺) ≥ 0.122(20) μN² reveals the predominant isovector nature of the 2₂⁺ state of ²⁰⁸Po

Inhibition of 2,5-hexanedione formation following exposure to n-hexane or a commercial hexane mixture

Bibliography: p. 99-11

Lifetime measurements in Nb99 and Zr99 : Investigation of shape coexistence

The ≈100 mass region is of special interest due to a rapid shape transition, observed by going from neutron number 58 to 60, especially pronounced in the Zr isotopes, where 98Zr is weakly and 100Zr is strongly deformed. To further examine this intricate phenomenon, in this work lifetimes of low-lying excited states in the nuclei 99Zr and 99Nb were determined using fast-timing techniques and an experimental setup consisting of four LaBr3⁢(Ce) detectors. Neutron rich =99 fragments were produced in neutron induced fission and separated by the spectrometer LOHENGRIN at the Institut Laue-Langevin in Grenoble, France. Experimental values are compared to two different calculations in the framework of the interacting boson-fermion model and discussed in the context of shape coexistence

Investigating the prolate-to-oblate shape phase transition: Lifetime measurements and γ spectroscopy of the low-lying negative parity structure in Os193

Excited states in 193Os were populated using a 192Os⁢( th., )⁢193Os thermal neutron capture reaction, with neutrons provided by the high-flux reactor of the Institut Laue-Langevin in Grenoble, France. Lifetimes of low-spin excited states were measured using the generalized centroid difference method. A total of eight mean lifetimes of low-lying excited states were determined for the first time, and limits for the lifetimes of three further excited states were established. Additionally, − angular correlations were analyzed to assign spins to previously known excited states up to 1 MeV, and extract multipole mixing ratios for several transitions. The new spectroscopic information is compared to calculations in the framework of the interacting boson-fermion model, based on the nuclear density functional theory, to investigate the prolate-to-oblate shape phase transition, predicted to occur in the neutron rich ≈190 region

Lifetime measurements and shape coexistence in Sr-97

Delayed gamma rays from neutron-rich A = 97 fission fragments were measured using the Lohengrin spectrometer at the high-flux reactor of the Institut Laue-Langevin in Grenoble. Several lifetimes of excited states in Sr-97 were measured using the fast-timing technique. The nucleus Sr-97 exhibits shape coexistence and is located exactly at the border of the spherical (N = 60) ground-state deformation. It is of particular interest to study the shape-coexisting structures at the spherical-deformed border (N = 59). The determined lifetimes within this work are compared to an interacting boson-fermion model calculation that is based on the microscopic energy density functional to provide a better understanding of the spherical-deformed border in strontium isotopes