Evaporation Channel as a Tool to Study Fission Dynamics

The dynamics of the fission process is expected to affect the evaporation residue cross section because of the fission hindrance due to the nuclear viscosity. Systems of intermediate fissility constitute a suitable environment for testing such hypothesis, since they are characterized by evaporation residue cross sections comparable or larger than the fission ones. Observables related to emitted charged particle, due to their relatively high emission probability, can be used to put stringent constraints on models describing the excited nucleus decay and to recognize the effects of fission dynamics. In this work model simulations are compared with the experimental data collected via the ^{32}S + ^{100}Mo reaction at E_{lab}= 200 MeV. By comparing an extended set of evaporation channel observables the limits of the statistical model and the large improvement coming by using a dynamical model are evidenced. The importance of using a large angular covering apparatus to extract the observable is stressed. The opportunity to measure more sensitive observables by a new detection device in operation at LNL are also discussed.Comment: v1: 7 pages, 6 figure

Italian physicists of all times: A biographical dictionary in preparation

This paper describes the historical research activity aimed at accomplishing the first prosopography of Italian physics. The investigation spans over a period of time of more than five centuries, starting from the Renaissance period and including the physicists born up to 1948. The data which are being collected will be articulated in a biographical dictionary, which is gradually being prepared and will be published in 10 separate dossiers. Up to now the research activity focused on the scholars who were active between the Risorgimento and World War II, allowing to list about 1000 Italian physicists born between 1770 and 1918. Many of them, including about 250 high school teachers, had been neglected so far by historical-scientific literature. Almost 100 women physicists were also identified, attesting a gradual evolution of Italian society and of its scientific culture. Concerning the above-mentioned period of time, the first four dossiers of the biographical dictionary (letters A–Z) are about to be completed and published within 2020. To show the significance of such a prosopographic investigation, a case study is described, concerning Enrico Stracciati (1858–1937), a little-known physicist who had an important role in Orso Mario Corbino’s education

Role of deformation in the decay of 56^{56}Ni and 40^{40}Ca di-nuclei

Inclusive as well as exclusive energy spectra of the light charged particles emitted in the $^{28}Si(E_{lab}=112.6 MeV) + ^{28}Si,^{12}C$ reactions have been measured at the Strasbourg VIVITRON facility in the angular range 15^0 - 150^0, using the ICARE multidetector array. The experimental energy spectra of $\alpha$-particles are generally well reproduced by the statistical model with a spin-dependent level density indicating the onset of defomations at high spin.Comment: 4 pages, 2 ps Figures included -- Talk given at the International Nuclear Physics Conference INPC98, Paris, France, August, 1998 (Proceedings to be published in Nuclear Physics A, 1999) -

Clustering effects in 48Cr composite nuclei produced via 24Mg + 24Mg reaction

In the framework of studying clustering effects in N=Z light nuclei, an experiment was carried out to get information on the properties of the 48 Cr composite nuclei produced via the 24 Mg +24 Mg reaction. In particular, the study regards the 48 Cr at 60 MeV of excitation energy where a resonance with a narrow width (170 KeV) has been found by measuring the elastic and anelastic channels. To determine the deformation of this state, evaporative Light Charged Particles (LCP) are measured and compared to the Statistical Model (SM) predictions, which are very sensitive to nuclear deformation. The experiment was performed at LNL using the 8ĒLP apparatus to select LCPs and a Parallel Plate Avalanche Counter (PPAC) system to detect the Evaporation Residues (ER). Preliminary results on the measurements of ER – LCP and LCP – LCP angular correlations are presented which indicate the presence of a very large deformation.The analysis will proceed with the extraction of the LCP energy spectra and with the angular correlations for high multiplicity channels to determine the deformation

Examination of isospin effects in multi-dimensional Langevin fission dynamics

Abstract One-dimensional and three-dimensional dynamical fission calculations based on Langevin equations are performed for the compound nuclei 194 Pb, 200 Pb, 206 Pb, 182 Hg, and 204 Hg to investigate the influence of the compound nucleus isospin on the prescission particle multiplicities and on the fission fragment mass–energy distribution. It is found that the prescission neutron, proton, and alpha particle multiplicities have approximately the same sensitivity to the dissipation strength for a given nucleus. This is at variance with conclusions of recent papers. The sensitivity of the calculated prescission particle multiplicities to the dissipation strength becomes higher with decreasing isospin of fissioning compound nucleus, and the increase of prescission particle multiplicities could reach 200%, when the reduction coefficient of one-body viscosity k s increases from 0.1 to 1, for the most neutron deficient nuclei considered. The variances of fission fragment mass and kinetic energy distributions are less sensitive to the change of dissipation strength than the prescission light particle multiplicities. A comparison to experimental data concerning 200 Pb nucleus is also presented

Characterization of New TRPM8 Modulators in Pain Perception

Background: Transient Receptor Potential Melastatin-8 (TRPM8) is a non-selective cation channel activated by cold temperature and by cooling agents. Several studies have proved that this channel is involved in pain perception. Although some studies indicate that TRPM8 inhibition is necessary to reduce acute and chronic pain, it is also reported that TRPM8 activation produces analgesia. These conflicting results could be explained by extracellular Ca2+-dependent desensitization that is induced by an excessive activation. Likely, this effect is due to phosphatidylinositol 4,5-bisphosphate (PIP2) depletion that leads to modification of TRPM8 channel activity, shifting voltage dependence towards more positive potentials. This phenomenon needs further evaluation and confirmation that would allow us to understand better the role of this channel and to develop new therapeutic strategies for controlling pain. Experimental approach: To understand the role of TRPM8 in pain perception, we tested two specific TRPM8-modulating compounds, an antagonist (IGM-18) and an agonist (IGM-5), in either acute or chronic animal pain models using male Sprague-Dawley rats or CD1 mice, after systemic or topical routes of administration. Results: IGM-18 and IGM-5 were fully characterized in vivo. The wet-dog shake test and the body temperature measurements highlighted the antagonist activity of IGM-18 on TRPM8 channels. Moreover, IGM-18 exerted an analgesic effect on formalin-induced orofacial pain and chronic constriction injury-induced neuropathic pain, demonstrating the involvement of TRPM8 channels in these two pain models. Finally, the results were consistent with TRPM8 downregulation by agonist IGM-5, due to its excessive activation. Conclusions: TRPM8 channels are strongly involved in pain modulation, and their selective antagonist is able to reduce both acute and chronic pain

Examination of isospin effects in multi-dimensional Langevin fission dynamics

One-dimensional and three-dimensional dynamical fission calculations based on Langevin equations are performed for the compound nuclei Pb-194, Pb-200, Pb-206, Hg-182, and Hg-204 to investigate the influence of the compound nucleus isospin on the prescission particle multiplicities and oil the fission fragment mass-energy distribution It is found that the prescission neutron, proton, and alpha particle multiplicities have approximately the same sensitivity to the dissipation strength for a given nucleus This is at variance with Conclusions of recent papers The sensitivity of the calculated prescission particle Multiplicities to the dissipation strength becomes higher with decreasing isospin of fissioning compound nucleus, and the increase of prescission particle multiplicities could reach 200%, when the reduction coefficient of one-body viscosity k(s) increases from 0 1 to 1, for the most neutron deficient nuclei considered The variances of fission fragment mass and kinetic energy distributions are less sensitive to the change of dissipation strength than the prescission light particle multiplicities A comparison to experimental data concerning Pb-200 nucleus is also presented