2.2 General formulae for beta-decay

Behrens, H.; Jänecke, J.

doi:10.1007/10201072_2

Cited by 6 publications

(4 citation statements)

References 11 publications

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“…This method greatly increases the speed of the simulation by bypassing the decay of radionuclides process used by Geant4. The β + spectra of three commonly used radionuclides ( 11 C, 15 O and 18 F) have been parametrized in GATE according to the Landolt-Börnstein tables (Behrens and Janecke 1969).…”

Section: Positron Emissionmentioning

confidence: 99%

GATE: a simulation toolkit for PET and SPECT

et al. 2004

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Monte Carlo simulation is an essential tool in emission tomography that can assist in the design of new medical imaging devices, the optimization of acquisition protocols and the development or assessment of image reconstruction algorithms and correction techniques. GATE, the Geant4 Application for Tomographic Emission, encapsulates the Geant4 libraries to achieve a modular, versatile, scripted simulation toolkit adapted to the field of nuclear medicine. In particular, GATE allows the description of time-dependent phenomena such as source or detector movement, and source decay kinetics. This feature makes it possible to simulate time curves under realistic acquisition conditions and to test dynamic reconstruction algorithms. This paper gives a detailed description of the design and development of GATE by the OpenGATE collaboration, whose continuing objective is to improve, document and validate GATE by simulating commercially available imaging systems for PET and SPECT. Large effort is also invested in the ability and the flexibility to model novel detection systems or systems still under design. A public release of GATE licensed under the GNU Lesser General Public License can be downloaded at http:/www-lphe.epfl.ch/GATE/. Two benchmarks developed for PET and SPECT to test the installation of GATE and to serve as a tutorial for the users are presented. Extensive validation of the GATE simulation platform has been started, comparing simulations and measurements on commercially available acquisition systems. References to those results are listed. The future prospects towards the gridification of GATE and its extension to other domains such as dosimetry are also discussed.

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Section: Positron Emissionmentioning

confidence: 99%

GATE: a simulation toolkit for PET and SPECT

et al. 2004

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“…The Coulomb interaction between the outgoing electron and the daughter nucleus, described by the relativistic Fermi function F, must be corrected by the screening effect of the orbital electrons left behind from the tritium molecule, which affects the Coulomb field of the daughter T 3 He + pair of nuclei. This introduces a multiplicative factor S [71].…”

Section: Theoretical Corrections To the Tritium Spectrummentioning

confidence: 99%

Sensitivity of next-generation tritium beta-decay experiments for keV-scale sterile neutrinos

Mertens

Lasserre

Groh

et al. 2015

J. Cosmol. Astropart. Phys.

104

102

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We investigate the sensitivity of tritium β-decay experiments for keV-scale sterile neutrinos. Relic sterile neutrinos in the keV mass range can contribute both to the cold and warm dark matter content of the universe. This work shows that a large-scale tritium beta-decay experiment, similar to the KATRIN experiment that is under construction, can reach a statistical sensitivity of the active-sterile neutrino mixing of sin 2 θ ∼ 10 −8 . The effect of uncertainties in the known theoretical corrections to the tritium β-decay spectrum were investigated, and found not to affect the sensitivity significantly. It is demonstrated that controlling uncorrelated systematic effects will be one of the main challenges in such an experiment.is one of the most intriguing questions of modern physics, since the Standard Model of elementary particle physics (SM) does not provide a suitable dark matter candidate. Such a candidate should be electrically neutral, at most weakly interacting, and stable with respect to the age of the universe.Relic active neutrinos, forming hot dark matter (HDM), are firmly ruled out as the dominant dark matter component. At the time of structure formation, light neutrinos had relativistic velocities and a large free streaming length, leading to a washing-out of smallscale structures, which is in disagreement with observations [16,17]. Consequently, the most most favored candidate was thought to be a cold dark matter (CDM) particle, the so-called weakly interacting massive particle (WIMP). Its freeze-out in the early universe occurs at non-relativistic velocities, preventing the washing-out of small-scale structures. Furthermore, the existence of WIMPs is independently motivated by theories extending the SM, such as Supersymmetry [18]. WIMPs are actively sought in direct and indirect measurements, but no solid evidence for their existence yet has been reported [19].Relic sterile neutrinos, with a mass in the keV range, are a candidate for both warm and cold dark matter (WDM and CDM) [8][9][10][11][12][13][14]. WDM and CDM scenarios fit the largescale structure data equally well [20]. On the galactic scale WDM scenarios predict a smaller number of dwarf satellite galaxies and shallower galactic density profiles than CDM, resolving tensions between observations of galaxy-size objects and specific CDM model simulations [21][22][23][24][25][26][27][28][29][30][31].Astrophysical observations constrain the sterile neutrino mass m s and active-sterile mixing angle θ. A robust and model-independent lower bound on the mass of spin-one-half dark matter particles is derived by considering the phase-space density evolution of dwarf spheroidal satellites in the Milky Way, leading to a mass limit of m s >1 keV [32,33]. Another sensitive observable is the X-ray emission line at half of the neutrino mass, arising from the decay of a keV-scale sterile neutrino into an active neutrino and a photon, which can be searched for with appropriate X-ray Space Telescopes, such as XMM-Newton [34] and Chandra [35]. A combination ...

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“…However, for forbidden decays, the full machinery is needed. According to Behrens and Büring, [17], the shape factor can be simplified somewhat for unique K-forbidden processes:…”

Section: Neutrino-nucleus Cross Sectionmentioning

confidence: 99%

“…The details of the calculations of the coefficients can be found in [17]; for now, suffice it to say they depend on the electron energy and momentum and the nuclear charge and radius. From a computational point of view, the main problem in the calculation of eq.…”

Section: Neutrino-nucleus Cross Sectionmentioning

confidence: 99%

Galactic abundances as a relic neutrino detection scheme

Riis

Zinner

Hannestad

2011

J. Cosmol. Astropart. Phys.

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We propose to use the threshold-free process of neutrino capture on β-decaying nuclei (NCB) using all available candidate nuclei in the Milky Way as target material in order to detect the presence of the Cosmic neutrino background (CνB). By integrating over the lifetime of the galaxy one might be able to see the effect of NCB processes as a slightly eschewed abundance ratio of selected βdecaying nuclei. First, the candidates must be chosen so that both the mother and daughter nuclei have a lifetime comparable to that of the Milky Way or the signal could be easily washed out by additional decays. Secondly, relic neutrinos have so low energy that their de Broglie wavelengths are macroscopic and they may therefore scatter coherently on the electronic cloud of the candidate atoms. One must therefore compare the cross sections for the two processes (induced βdecay by neutrino capture, and coherent scattering of the neutrinos on atomic nuclei) before drawing any conclusions. Finally, the density of target nuclei in the galaxy must be calculated. We assume supernovae as the only production source and approximate the neutrino density as a homogenous background. Here we perform the full calculation for 187 Re and 138 La and find that one needs abundance measurements with 24 digit precision in order to detect the effect of relic neutrinos. Or alternatively an enhancement of ρ ν by a factor of ∼ 10 15 to produce an effect within the current abundance measurement precision.

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2.2 General formulae for beta-decay

Cited by 6 publications

References 11 publications

GATE: a simulation toolkit for PET and SPECT

GATE: a simulation toolkit for PET and SPECT

Sensitivity of next-generation tritium beta-decay experiments for keV-scale sterile neutrinos

Galactic abundances as a relic neutrino detection scheme

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