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Particle identification using current maximum obtained from charge
Get PDFParticle identification plays a crucial role in the study of isospin dynamics, and several identification techniques have been developed in the last decades. Amongst them, the pulse shape analysis methods allow to identify those
fragments that are fully stopped in a single detector layer by studying the shape of the signal induced by the impinging fragment. The correlation of the maximum of
the induced current signal with the energy of the fragment is known to give a good isotopic identification, but requires to acquire the current signal. However, when
the current signal isn’t available, it can be reconstructed from the digitized charge signal. The algorithms used for the reconstruction are presented briefly along with the first results obtained during the DIGIGARF experiment at LNL
Durability of targets and foils in experiments on synthesis of superheavy nuclei
Get PDFDurability of targets and window foils irradiated by intense heavy ion (HI) beams in the experiments on synthesis of superheavy nuclei (SHN), which are carried out in Dubna with a Gas-Filled Recoil Separator (DGFRS), has been considered. High fluxes of HIs and heat generated within relatively small areas and thicknesses of the target and foils are inherent in such long-term experiments. The
ability of these elements to withstand radiation damages, sputtering and evaporation of atoms becomes questionable. All the processes are influenced by the target (foil) temperature and none of them is independent of the others, but they can be considered separately. Thus, sputtering yields were approximated on the grounds of available models and experimental data and compared to the results of measurements carried out to verify the estimates. The temperature of the target (foil), in turn, was estimated in the conditions of pulse heating followed by subsequent cooling with a radiation emitted from their surfaces. These conditions correspond to the rotating target and window irradiated by a continuous HI beam in the DGFRS experiments. Estimates show that radiative cooling might be the most effective way of heat removal at the temperature of few hundred Celsius degrees
New physics searches with LUX and LZ
Get PDFThe frontier of experimental particle physics research, especially astroparticle physics, frequently involves the detection of signals that are both rare (fewer than an event per year per kilogram), and small (energy depositions at the keV scale). A prime example is the direct search for dark matter, although other signatures for new physics are also being sought, such as axions and various neutrino signals. The key technology that has evolved to meet this challenge is that of the ultra low background two-phase time projection chamber, deployed deep underground. The Large Underground Xenon (LUX) instrument was a leading
device of this type. Now dismantled to make way for its successor, analysis of legacy data continues. The main scientific results of LUX are presented. With 50 times larger fiducial (usable) mass, and increased background rejection power, LUX-ZEPLIN (LZ) is presently under construction and is due to take first data in 2020. It will have a sensitivity at least two orders of magnitude beyond current best limits for the leading dark matter candidates. An overview of the LZ experiment is presented
DarkSide status and prospects
Get PDFDarkSide uses a dual-phase Liquid Argon Time Projection Chamber to search for WIMP dark matter. The current detector, DarkSide-50, is running since mid 2015 with a target of 50 kg of Argon from an underground source. Here it is presented the latest results of searches of WIMP-nucleus interactions, with WIMP masses in the GeV-TeV range, and of WIMP-electron interactions, in the sub-GeV mass range. The future of DarkSide with a new generation experiment, involving a global collaboration from all the current Argon based experiments, is presented
Error analysis of the parameters of the Skyrme N2LO pseudo-potential
Get PDFWe perform a detailed analysis of the parameters of the Skyrme SN2LO interaction. By mean of a covariance matrix analysis, we have been able to provide error bars and build the complete covariance matrix. The latter will be used in future applications to properly study the propagation of errors on nuclear observables calculated with this pseudo-potential
Perspectives on the measurement of competitive double gamma decay with the AGATA tracking array
Get PDFThe double-gamma decay is a second order electromagnetic process where two photons are emitted simultaneously. It is characterized by low branching ratios, making its measurement interesting both theoretically and also experimentally. Although this process has been already observed in the past, a recent publication claimed its observation in competition with the single gamma decay.
A measurement of this process with the AGATA spectrometer (Advanced GAmma Tracking Array) will deliver more detailed results. A test of feasibility of this challenging measurement has been performed through GEANT4 simulations of the decay of the 137Ba isotope. Particular emphasis is placed on the tracking algorithm which allows to reconstruct a scattering gamma-ray event based on the position and energy of every interaction point within the AGATA germanium detector
Test of a 3He target for transfer reactions in inverse kinematics
Get PDFWith the aim of studying exotic nuclei close to the proton dripline, an innovative 3He target was produced and tested in a collaboration between the Materials Science Institute of Seville (Spain) and the Legnaro National Laboratories
(Italy). The target was manufactured with a new technique that aims to reduce the costs while providing high quality targets. The target was tested at the Legnaro National Laboratories. The results of this test are presented in this contribution
Relevance of neutron excess in nuclear matter to proton-induced composite-particle pre-equilibrium emission
Get PDFFormulation of the equation of state (EoS) of nuclear matter has far-reaching implications for issues ranging from the atomic nucleus to crucial aspects of astrophysics. Recent investigations of the influence of the formation of light ion clusters on the development of the EoS are of interest. A study based on a generalized relativistic mean-field model revealed an isotope-dependant quenching of α-clustering on the surface of Sn as the nuclear system becomes more asymmetric. This trend of decreasing α-clustering with increasing mass number of Sn was previously found to be consistent with existing experimental results of an αpickup reaction. The implications of predictions of the EoS are discussed as being of profound interest to proton-induced α-particle pre-equilibrium emission at incident energies above about 100 MeV
Dynamics of nucleus-nucleus collisions and neutron rearrangement in time-dependent approach
Get PDFThe dynamical approach based on numeric solution of the timedependent Schr¨odinger equation is applied to description of transfer and rearrangement of nucleons in nucleus-nucleus collisions. The results of calculation of neutron transfer cross sections for reaction 6He + 197Au and total reaction cross sections for reactions 6He + 28Si, 9Li + 28Si are in agreement with experimental data
Non-occlusive Mesenteric Ischaemia and Acute Kidney Injury: A Case Report of Severe Idiopathic Systemic Capillary Leak Syndrome
Get PDFSystemic capillary leak syndrome is a rare, underdiagnosed and life-threatening disease characterized by periodic episodes of hypovolaemic shock due to leakage of plasma from the intravascular to the extravascular space. It is associated with haemoconcentration, hypoalbuminaemia and generalized oedema. We report the case of a patient with a history of emergent extensive small and large bowel resection and several episodes of hypovolaemic shock with acute renal injury, who presented with abdominal pain, headache and generalized oedema. Severe systemic capillary leak syndrome was diagnosed after a complex diagnostic approach. This case report describes the acute and prophylactic treatment administered to the patient and the 4-year follow-up. We highlight the importance of timely recognition and prompt treatment, as well as the need for new investigations to prevent the serious and unusual complications seen in this case