Search results for "energy [particle]"
showing 10 items of 22753 documents
r Process (n, γ) Rate Constraints from the γ Emission of Neutron Unbound States in β decay
2017
Total absorption gamma-ray spectroscopy is used to measure accurately the intensity of γγ emission from neutron-unbound states populated in the ββ-decay of delayed-neutron emitters. From the comparison of this intensity with the intensity of neutron emission a constraint on the (n, γγ) cross section for highly unstable neutron-rich nuclei can be deduced. A surprisingly large γγ branching was observed for a number of isotopes which might indicate the need to increase by a large factor the Hauser-Feshbach (n, γγ) cross-section estimates that impact on r process abundance calculations. peerReviewed
Total absorption spectroscopy study of the β decay of 86Br and 91Rb
2017
The beta decays of 86Br and 91Rb have been studied using the total absorption spectroscopy technique. The radioactive nuclei were produced at the Ion Guide Isotope Separator On-Line facility in Jyväskylä and further purified using the JYFLTRAP. 86Br and 91Rb are considered to be major contributors to the decay heat in reactors. In addition, 91Rb was used as a normalization point in direct measurements of mean gamma energies released in the beta decay of fission products by Rudstam et al. assuming that this decay was well known from high-resolution measurements. Our results show that both decays were suffering from the Pandemonium effect and that the results of Rudstam et al. should be renor…
Calibration of a small anode germanium well detector
2017
SAGe kolokiteen kalibroinnit suoritettiin kolmelle näytegeometrialle. Kaksi geometrioista oli sylinterin muotoisia purkkeja, jotka mitattiin ilmaisimen päällä ja yksi koeputki, joka mitattiin kolon sisällä. Piikkitehokkuuskalibrointi tehtiin NPL:sta tilattujen sertifioitujen näytteiden avulla. Yksinuklidinäytteitä valmistettiin radioaktiivisista liuoksista totaalitehokkuuskalibrointia varten. Totaalitehokkuuskäyrä saatiin simuloimalla totaalitehokkuudet MCNP:llä ja sovittamalla malli vastaamaan kokeellisia tuloksia. Kalibraatiot tehtiin energiavälille 30 keV–1.9 MeV. Kalibroinnit olivat tarpeeksi luotettavia, että ilmaisinta voidaan käyttää akkreditoiduissa gammaspektrometrisissä mittauksis…
Three-dimensional core-collapse supernovae with complex magnetic structures: I. Explosion dynamics
2021
Magnetic fields can play a major role in the dynamics of outstanding explosions associated to violent events such as GRBs and hypernovae, since they provide a natural mechanism to harness the rotational energy of the central proto-neutron star and power relativistic jets through the stellar progenitor. As the structure of such fields is quite uncertain, most numerical models of MHD-driven core-collapse supernovae consider an aligned dipole as initial magnetic field, while the field's morphology can actually be much more complex. We present three-dimensional simulations of core-collapse supernovae with more realistic magnetic structures, such as quadrupolar fields and, for the first time, an…
The impact of non-dipolar magnetic fields in core-collapse supernovae
2019
The magnetic field is believed to play an important role in at least some core-collapse supernovae if its magnitude reaches $10^{15}\,\rm{G}$, which is a typical value for a magnetar. In the presence of fast rotation, such a strong magnetic field can drive powerful jet-like explosions if it has the large-scale coherence of a dipole. The topology of the magnetic field is, however, probably much more complex with strong multipolar and small-scale components and the consequences for the explosion are so far unclear. We investigate the effects of the magnetic field topology on the dynamics of core-collapse supernovae and the properties of forming proto-neutron star (PNS) by comparing pre-collap…
On the effects of transmit power control on the energy consumption of WiFi network cards
2009
Transmit power control has been largely proposed as a solution to improve the performance of packet radio systems in terms of increased throughput, spatial reuse and battery lifetime for mobile terminals. However, the benefits of transmit power control schemes on these different performance figures may strongly depend on the employed PHY technology and channel access mechanism. In this paper, we focus on the effects of power control on the energy consumption of WiFi network cards. By means of several experimental tests carried out under different operation conditions and modulation schemes, we try to justify why the reduction of the transmission power has a marginal effect on the overall en…
Energy efficient model for biogas production in farm scale
2011
Energy efficient solutions for six farm biogas production was found by calculating mass and energy balance in different scenarios. Raw materials in biogas production were cow manure and grass silage that were produced in these farms. There were calculated mass and energy balances on average for one year biogas prouduction that consisted of grass silage production, raw material transportation and biogas production in the biogas plant. In addition, direct greenhouse gases from biogas production were estimated. The direct mass and energy flows were calculated. It turned out that one input energy unit can produce 5.0 to 5.5 energy units as heat and electricity. Biogas reactor consumed heat from…
Search for photonic signatures of gauge-mediated supersymmetry in 8TeV pp collisions with the ATLAS detector
2015
A search is presented for photonic signatures motivated by generalized models of gauge-mediated supersymmetry breaking. This search makes use of 20.3 fb[superscript −1] of proton-proton collision data at √s = 8 TeV recorded by the ATLAS detector at the LHC, and explores models dominated by both strong and electroweak production of supersymmetric partner states. Four experimental signatures incorporating an isolated photon and significant missing transverse momentum are explored. These signatures include events with an additional photon, lepton, b-quark jet, or jet activity not associated with any specific underlying quark flavor. No significant excess of events is observed above the Stand…
Recommendations of the LHC Dark Matter Working Group: Comparing LHC searches for dark matter mediators in visible and invisible decay channels and ca…
2019
Physics of the Dark Universe 26, 100377 (2019). doi:10.1016/j.dark.2019.100377
Stationary, Second Use Battery Energy Storage Systems and Their Applications: A Research Review
2021
The global demand for electricity is rising due to the increased electrification of multiple sectors of economic activity and an increased focus on sustainable consumption. Simultaneously, the share of cleaner electricity generated by transient, renewable sources such as wind and solar energy is increasing. This has made additional buffer capacities for electrical grids necessary. Battery energy storage systems have been investigated as storage solutions due to their responsiveness, efficiency, and scalability. Storage systems based on the second use of discarded electric vehicle batteries have been identified as cost-efficient and sustainable alternatives to first use battery storage syste…