549 research outputs found
An iterative procedure to obtain inverse response functions for thick-target correction of measured charged-particle spectra
A new method for correcting charged-particle spectra for thick target effects
is described. Starting with a trial function, inverse response functions are
found by an iterative procedure. The variances corresponding to the measured
spectrum are treated similiarly and in parallel. Oscillations of the solution
are avoided by rebinning the data to finer bins during a correction iteration
and back to the original or wider binning after each iteration. This
thick-target correction method has been used for data obtained with the MEDLEY
facility at the The Svedberg Laboratory, Uppsala, Sweden, and is here presented
in detail and demonstrated for two test cases.Comment: 14 pages, 8 figures, submitted to NIM
Federal Tax Concepts as a Guide for State Apportionment of Dividends
In ASARCO, Inc. v. Idaho State Tax Commission, the Supreme Court rejected Idaho’s definition of income, and limited the apportionability of dividends, interest, and capital gains. The Court held that a unitary business relationship did not exist between ASARCO and the dividend payors, but did not address whether such a relationship was a sufficient precondition or a necessary one.
This article addresses two federal tax doctrines that may provide insight into state taxation of dividends: (1) the “effectively connected” doctrine, and (2) the Corn Products doctrine. The article first provides a detailed examination of the facts in ASARCO, and discusses the Court’s holding. The article explains that Idaho’s sweeping definition of income, which conflated business and nonbusiness income, invited the Court’s rejection. Next, the article examines the applicability of Mobil Oil Corp. v. Commissioner of Taxes of Vermont, and how that holding is not dispositive regarding the apportionability of dividends in general. Finally, the article discusses the two aforementioned federal tax doctrines. These two doctrines do not expressly address the characterization of dividends as business income, but implicate the same underlying issue. The article concludes by explaining that the tax treatment of dividends and capital gains as business income is not unique to state taxation
Tutorial on Neutron Physics in Dosimetry
Almost since the time of the discovery of the neutron more than 70 years ago,
efforts have been made to understand the effects of neutron radiation on tissue
and, eventually, to use neutrons for cancer treatment. In contrast to charged
particle or photon radiations which directly lead to release of electrons,
neutrons interact with the nucleus and induce emission of several different
types of charged particles such as protons, alpha particles or heavier ions.
Therefore, a fundamental understanding of the neutron-nucleus interaction is
necessary for dose calculations and treatment planning with the needed
accuracy. We will discuss the concepts of dose and kerma, neutron-nucleus
interactions and have a brief look at nuclear data needs and experimental
facilities and set-ups where such data are measured.Comment: Invited talk at the 11th Neutron and Ion Dosimetry Symposium
NEUDOS-11, October 11-16, 2009, Cape Town, South Africa. 14 pages, 8 figures;
submitted to Radiation Measurement
Exploring Pd adsorption, diffusion, permeation, and nucleation on bilayer SiO<sub>2</sub>/Ru as a function of hydroxylation and precursor environment: From UHV to catalyst preparation
The hydroxylation-dependent permeability of bilayer SiO2 supported on Ru(0001) was investigated by XPS and TDS studies in a temperature range of 100K to 600K. For this, the thermal behavior of Pd evaporated at 100K, which results in surface and sub-surface (Ru-supported) binding arrangements, was examined relative to the extent of pre-hydroxylation. Samples containing only defect-mediated hydroxyls showed no effect on Pd diffusion through the film at low temperature. If, instead, the concentration of strongly bound hydroxyl groups and associated weakly bound water molecules was enriched by an electron-assisted hydroxylation procedure, the probability for Pd diffusion through the film is decreased via a pore-blocking mechanism. Above room temperature, all samples showed similar behavior, reflective of particle nucleation above the film and eventual agglomeration with any metal atoms initially binding beneath the film. When depositing Pd onto the same SiO2/Ru model support via adsorption of [Pd(NH3)4]C2 from alkaline (pH12) precursor solution, we observe notably different adsorption and nucleation mechanisms. The resultant Pd adsorption complexes follow established decomposition pathways to produce model catalyst systems compatible with those created exclusively within UHV despite lacking the ability to penetrate the film due to the increased size of the initial Pd precursor groups
Sensitivity of measured fission yields on prompt-neutron corrections
The amount of emitted prompt neutrons from the fission fragments increases as
a function of excitation energy. Yet it is not fully understood whether the
increase in \nu(A) as a function of E_{n} is mass dependent. The share of
excitation energies among the fragments is still under debate, but there are
reasons to believe that the excess in neutron emission originates only from the
heavy fragments, leaving \nu_{light}(A) almost unchanged. In this work we
investigated the consequences of a mass-dependent increase in \nu(A) on the
final mass and energy distributions. The assumptions on \nu(A) are essential
when analysing measurements based on the 2E-technique. This choice showed to be
significant on the measured observables. For example, the post-neutron emission
mass yield distribution revealed changes up to 10-30%. The outcome of this work
pinpoint the urgent need to determine \nu(A) experimentally, and in particular,
how \nu(A) changes as a function of incident-neutron energy. Until then, many
fission yields in the data libraries could be largely affected, since they were
analysed based on another assumption on the neutron emission.Comment: 4 pages, 3 figures, Proc. 2013 International Conference on Nuclear
Data for Science & Technology (ND2013), March 4-8, 2013, New York, USA, to be
published in Nuclear Data Sheet
Light-ion production in the interaction of 96 MeV neutrons with oxygen
Double-differential cross sections for light-ion (p, d, t, He-3 and alpha)
production in oxygen, induced by 96 MeV neutrons are reported. Energy spectra
are measured at eight laboratory angles from 20 degrees to 160 degrees in steps
of 20 degrees. Procedures for data taking and data reduction are presented.
Deduced energy-differential and production cross sections are reported.
Experimental cross sections are compared to theoretical reaction model
calculations and experimental data at lower neutron energies in the literature.
The measured proton data agree reasonably well with the results of the model
calculations, whereas the agreement for the other particles is less convincing.
The measured production cross sections for protons, deuterons, tritons and
alpha particles support the trends suggested by data at lower energies.Comment: 21 pages, 13 figures, submitted to Phys. Rev.
Ion counting efficiencies at the IGISOL facility
At the IGISOL-JYFLTRAP facility, fission mass yields can be studied at high
precision. Fission fragments from a U target are passing through a Ni foil and
entering a gas filled chamber. The collected fragments are guided through a
mass separator to a Penning trap where their masses are identified. This
simulation work focuses on how different fission fragment properties (mass,
charge and energy) affect the stopping efficiency in the gas cell. In addition,
different experimental parameters are varied (e. g. U and Ni thickness and He
gas pressure) to study their impact on the stopping efficiency. The simulations
were performed using the Geant4 package and the SRIM code. The main results
suggest a small variation in the stopping efficiency as a function of mass,
charge and kinetic energy. It is predicted that heavy fragments are stopped
about 9% less efficiently than the light fragments. However it was found that
the properties of the U, Ni and the He gas influences this behavior. Hence it
could be possible to optimize the efficiency.Comment: 52 pages, 44 figure
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