57 research outputs found
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
Inhibition of 2,5-hexanedione formation following exposure to n-hexane or a commercial hexane mixture
Bibliography: p. 99-11
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
Lifetime measurements in <math><mmultiscripts><mi>Mo</mi><mprescripts/><none/><mn>92</mn></mmultiscripts></math>: Investigation of seniority conservation in the <math><mrow><mi>N</mi><mo>=</mo><mn>50</mn></mrow></math> isotones
International audienceExcited states in the yrast and negative parity bands in Mo92 were populated in two different experiments using the Zr90(α,2n)Mo92 and Nb93(p,2n)Mo92 fusion-evaporation reactions at the Cologne FN Tandem accelerator and measured using a hybrid setup of high purity germanium and lanthanum bromide detectors. Lifetimes of the excited 21+, 41+, 61+, 81+, 51−, 71−, and 91− states were measured using the γ-γ fast-timing technique. The newly measured lifetime of the 41+ state differs from the recently published value measured using the recoil distance Doppler shift method. Experimental B(E2) strengths of excited states in Mo92 are used to predict theoretical B(E2) values in the N=50 isotones from Tc93 up to Rh95 using semiempirical calculations in the single-j orbital 0g9/2 for the protons
Triaxiality in the mid-shell nucleus Pd-112
Lifetimes of low-spin excited states in Pd-112 were measured using the recoil-distance Doppler-shift technique. The nucleus of interest was populated in a (110)pd(O-18, O-16)Pd-112 reaction using the Cologne FN Tandem accelerator. Three lifetimes of ground-state band members and one lifetime of the y band were measured. From these lifetimes reduced transition probabilities were extracted and compared to interacting boson model, gamma-soft calculations, and Davydov calculations. The lifetime of the 2(gamma)(+) gives some insights on the nuclear shape and structure of the gamma band. The deduced transition rates show an indicator for a rigid triaxial nucleus as well as more indicators for a gamma-soft nucleus
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