An improvement of the Berry--Esseen inequality with applications to Poisson and mixed Poisson random sums

By a modification of the method that was applied in (Korolev and Shevtsova, 2009), here the inequalities $$\rho(F_n,\Phi)\le\frac{0.335789(\beta^3+0.425)}{\sqrt{n}}$$ and $$\rho(F_n,\Phi)\le \frac{0.3051(\beta^3+1)}{\sqrt{n}}$$ are proved for the uniform distance $\rho(F_n,\Phi)$ between the standard normal distribution function $\Phi$ and the distribution function $F_n$ of the normalized sum of an arbitrary number $n\ge1$ of independent identically distributed random variables with zero mean, unit variance and finite third absolute moment $\beta^3$. The first of these inequalities sharpens the best known version of the classical Berry--Esseen inequality since $0.335789(\beta^3+0.425)\le0.335789(1+0.425)\beta^3<0.4785\beta^3$ by virtue of the condition $\beta^3\ge1$, and 0.4785 is the best known upper estimate of the absolute constant in the classical Berry--Esseen inequality. The second inequality is applied to lowering the upper estimate of the absolute constant in the analog of the Berry--Esseen inequality for Poisson random sums to 0.3051 which is strictly less than the least possible value of the absolute constant in the classical Berry--Esseen inequality. As a corollary, the estimates of the rate of convergence in limit theorems for compound mixed Poisson distributions are refined.Comment: 33 page

Cascaded Multilevel Inverter-Based Asymmetric Static Synchronous Compensator of Reactive Power

The topology of the static synchronous compensator of reactive power for a low-voltage three-phase utility grid capable of asymmetric reactive power compensation in grid phases has been proposed and analysed. It is implemented using separate, independent cascaded H-bridge multilevel inverters for each phase. Every inverter includes two H-bridge cascades. The first cascade operating at grid frequency is implemented using thyristors, and the second one—operating at high frequency is based on the high-speed MOSFET transistors. The investigation shows that the proposed compensator is able to compensate the reactive power in a low-voltage three-phase grid when phases are loaded by highly asymmetrical reactive loads and provides up to three times lower power losses in the compensator as compared with the situation when the compensator is based on the conventional three-level inverters implemented using IGBT transistors.publishedVersio

Development of the (d,n) proton-transfer reaction in inverse kinematics for structure studies

Transfer reactions have provided exciting opportunities to study the structure of exotic nuclei and are often used to inform studies relating to nucleosynthesis and applications. In order to benefit from these reactions and their application to rare ion beams (RIBs) it is necessary to develop the tools and techniques to perform and analyze the data from reactions performed in inverse kinematics, that is with targets of light nuclei and heavier beams. We are continuing to expand the transfer reaction toolbox in preparation for the next generation of facilities, such as the Facility for Rare Ion Beams (FRIB), which is scheduled for completion in 2022. An important step in this process is to perform the (d,n) reaction in inverse kinematics, with analyses that include Q-value spectra and differential cross sections. In this way, proton-transfer reactions can be placed on the same level as the more commonly used neutron-transfer reactions, such as (d,p), (9Be,8Be), and (13C,12C). Here we present an overview of the techniques used in (d,p) and (d,n), and some recent data from (d,n) reactions in inverse kinematics using stable beams of 12C and 16O.Comment: 9 pages, 4 figures, presented at the XXXV Mazurian Lakes Conference on Physics, Piaski, Polan

Systematics of low energy collective states in neutron-rich Cd isotopes

It has been shown that there are significant deviations from the expected U(5) dynamical symmetry for 110,112,114,116Cd. However, there is very significant mixing with intruder states in this region. In this paper, we investigated states in the heavier 120,124,126Cd populated via beta decay. These nuclei exhibit similar patterns to the lighter Cd isotopes even though the intruder states are much higher in energy. © Published under licence by IOP Publishing Ltd

Impact of Modular Total Absorption Spectrometer measurements of β decay of fission products on the decay heat and reactor ν e flux calculation

We report the results of a β-decay study of fission products Br86, Kr89, Rb89, Rb90gs, Rb90m, Kr90, Rb92, Xe139, and Cs142 performed with the Modular Total Absorption Spectrometer (MTAS) and on-line mass-separated ion beams. These radioactivities were assessed by the Nuclear Energy Agency as having high priority for decay heat analysis during a nuclear fuel cycle. We observe a substantial increase in β feeding to high excited states in all daughter isotopes in comparison to earlier data. This increases the average γ-ray energy emitted by the decay of fission fragments during the first 10 000 s after fission of U235 and Pu239 by approximately 2% and 1%, respectively, improving agreement between results of calculations and direct observations. New MTAS results reduce the reference reactor νe flux used to analyze reactor νe interaction with detector matter. The reduction determined by the ab initio method for the four nuclear fuel components, U235, U238, Pu239, and Pu241, amounts to 0.976, 0.986, 0.983, and 0.984, respectively

β-Decay study of neutron-rich bromine and krypton isotopes

Short-lived neutron-rich nuclei including 93Br, 93Kr, and 94Kr were produced in proton-induced fission of 238U at the Holifield Radioactive Ion Beam Facility in Oak Ridge. Their β decay was studied by means of a high-resolution online mass separator and β-γ spectroscopy methods. The half-life of T1/2 = 152(8) ms and β-delayed branching ratio of Pn = 53-8+11% measured for 93Br differs from the previously reported values of T1/2 = 102(10) ms and Pn = 68(7)%. At the same time the half-life of 94Kr T1/2 = 227(14) ms and both the half-life of T1/2 = 1.298(54) s and β-delayed branching ratio of Pn = 1.9-0.2+0.6% of 93Kr are in very good agreement with literature values. The decay properties of 93Br include previously unreported γ transitions following β-delayed neutron emission. © 2013 American Physical Society

Long-lived isomeric states and quasiparticle band structures in neutron-rich Gd 162,164 nuclei from β decay

Neutron-rich nuclei Eu162,164 were produced by bombarding a proton beam on a U238 target at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory and mass separating the Eu162,164 products. New level schemes and new γ-ray transitions of the daughters Gd162,164 were identified from β-decay spectroscopy studies. Half-lives of the Eu162,164 were remeasured to clarify the previous ambiguous results. Two quasiparticle band structures were built and compared with neighboring nuclei. The β and γ bands were extended in Gd162 and a γ band was extended in Gd164. Half-lives of the isomeric states at (6-) 1449 keV in Gd162 and (4-) 1096 keV in Gd164 were measured to be 99(3) μs and 0.56(3) μs, respectively. Projected shell model calculations were performed and found to be in good agreement with all of the experimental data

New transitions and levels for Tb 163 obtained from β -decay studies

Transitions in Tb163 following β decay of Gd163 were obtained as part of investigations of γ rays emitted following Eu163β decay to Gd163. Detailed analysis of the low-energy structure of Tb163 has been carried out with these data to expand previous β-decay studies and reactions studies of levels in Tb163. Data were collected at the LeRIBSS station of the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory with an array of four Clover HPGe detectors for γ rays and two plastic scintillators for β detection. The γ rays were identified as belonging to Gd163 and Tb163 via mass selection and γ-γ-β, γ-γ, or γ-x-ray coincidence. In total, 38 new γ-ray transitions were observed in Tb163 from 15 newly identified levels and 12 previously identified levels. Potential energy surface calculations were performed which support a rigid prolate deformation. Previously identified unplaced transitions in Tb163 have been placed within the level scheme of Tb163 and additional states and transitions have been identified