Performances of keystone geometry micro-strip gas chambers

Abstract The performances of micro-strip gas chamber detectors with CF 4 counting gas have been tested with a 241 Am α source. The behaviour of the gain as a function of gas pressure, the dependence of the energy resolution on gas pressure and anode voltage, and the gain variation along the strip length due to the keystone geometry of the micro-strip pads are reported. An empirical response function to describe such a position dependence of the gain is proposed

Isotope analysis in central heavy ion collisions at intermediate energies

Symmetry energy is a key quantity in the study of the equation of state of asymmetric nuclear matter. Heavy ion collisions at low and intermediate energies, performed at Laboratori Nazionali di Legnaro and Laboratori Nazionali del Sud, can be used to extract information on the symmetry energy coefficient Csym, which is currently poorly known but relevant both for astrophysics and for structure of exotic nuclei.Comment: 2 pages, 1 figure. Proceedings of 7th International Conference on Radioactive Nuclear Beams (RNB7), to be published in The European Physical Journal

Više-fragmentna tvorba u reakcijama 32S+58,64Ni NA 11 A MeV

The characteristic features of the 32S+58,64Ni reaction at 11 A MeV have been investigated to evidence the possible rise of multi-fragmentation processes at low excitation energies. The importance of such phenomena consists in the fact that they could represent the signature of a nuclear phase transition from a liquid to a gas region. Evidence of multi-fragment production is displayed by the present data; even if the yield of such events is compatible with the predictions of statistical models, the partition of the mass of the decaying system cannot be easily reproduced. Some preliminary indications of isospin effects are suggested by looking at the differences between the two reacting systems.Istraživali smo značajke reakcije 32S+ 58,64Ni na 11 A MeV radi pronalaženja mogućeg porasta više-fragmentnih procesa na nižim uzbudnim energijama. Važnost se tih pojava sastoji u tome što bi one mogle predstavljati znakove nuklearnog faznog prijelaza od tekućeg u plinsko stanje. Znakovi tvorbe više fragmenata vide se u dobivenim podacima; no čak ako je i prinos tih događaja u skladu s predviđanjima statističkog modela, razdioba mase sustava koji se raspada ne uspijeva se objasniti. Usporedba dviju reakcija ukazuje na moguće izospinske efekte

Više-fragmentna tvorba u reakcijama 32S+58,64Ni NA 11 A MeV

The characteristic features of the 32S+58,64Ni reaction at 11 A MeV have been investigated to evidence the possible rise of multi-fragmentation processes at low excitation energies. The importance of such phenomena consists in the fact that they could represent the signature of a nuclear phase transition from a liquid to a gas region. Evidence of multi-fragment production is displayed by the present data; even if the yield of such events is compatible with the predictions of statistical models, the partition of the mass of the decaying system cannot be easily reproduced. Some preliminary indications of isospin effects are suggested by looking at the differences between the two reacting systems.Istraživali smo značajke reakcije 32S+ 58,64Ni na 11 A MeV radi pronalaženja mogućeg porasta više-fragmentnih procesa na nižim uzbudnim energijama. Važnost se tih pojava sastoji u tome što bi one mogle predstavljati znakove nuklearnog faznog prijelaza od tekućeg u plinsko stanje. Znakovi tvorbe više fragmenata vide se u dobivenim podacima; no čak ako je i prinos tih događaja u skladu s predviđanjima statističkog modela, razdioba mase sustava koji se raspada ne uspijeva se objasniti. Usporedba dviju reakcija ukazuje na moguće izospinske efekte

Mass and charge identification of fragments detected with the Chimera Silicon-CsI(Tl) telescopes

Mass and charge identification of charged products detected with Silicon-CsI(Tl) telescopes of the Chimera apparatus is presented. An identification function, based on the Bethe-Bloch formula, is used to fit empirical correlation between Delta E and E ADC readings, in order to determine, event by event, the atomic and mass numbers of the detected charged reaction products prior to energy calibration.Comment: 24 pages, 7 .jpg figures, submitted to Nucl.Instr.

On-line production of neutron rich isotopes from uranium carbide targets

Experiments done using on-line mass separation of neutron-rich nuclei produced by 1 GeV proton beam on natural U by spallation reactions are performed to study the characteristics of different UCx targets. Special attention is devoted to reliably extract isotopic yields in case of complex decay schemes and to the valuation of release efficiency of some isotopic chains. New gamma-branching measuremet for 92Rb are obtained. In addition, a formalism is developed to disantangle the contribution of β-decay in the target from direct production by fission and to provide more consistent data for the interpretation of release curves. Some results are shown for the Cs and Rb isotopic chains

Energy and Charge Calibration of CsI(Tl) Crystals of the GARFIELD Apparatus

22nonenoneM.FALSIORI; U.ABBODANNO; G.CASINI; M.CHIARI; M.DAGOSTINO; F.GRAMEGNA; A.L.LANCHAIS; P.M.MILAZZO; A.MORONI; A.ORDINE; F.TONETTO; L.VANNUCCI; P.F.MASTINU; A.BOLOGNA; S.CAVALLARO; M.L.FIANDRI; MARGAGLIOTTI G.V.; A.NANNINI; L.TRAVAGLINI; E.VARDACI; M.BRUNO; G.VANNINIM., Falsiori; U., Abbodanno; G., Casini; M., Chiari; M., Dagostino; F., Gramegna; A. L., Lanchais; P. M., Milazzo; A., Moroni; A., Ordine; F., Tonetto; L., Vannucci; P. F., Mastinu; A., Bologna; S., Cavallaro; M. L., Fiandri; Margagliotti, Giacomo; A., Nannini; L., Travaglini; E., Vardaci; M., Bruno; G., Vannin

Energy and charge calibration of CsI(Tl) crystals of the GARFIELD apparatus

Results are presented concerning a calibration experiment of the CsI(Tl) crystals of the GARFIELD apparatus. Experimental data were collected in a wide range of energy and charge (40 less than or equal to E(MeV) less than or equal to 230, 3 less than or equal to Z less than or equal to 28) with particular care to the region of low energies and light ions. Analytical expressions in recent publications, linking the output response of CsI(Tl) crystals to the energy and charge of the detected ion, are revised. An improved formula is suggested, which takes into account new physical constraints