Transcript Document
Abrasion -Fission The code operates under MS Windows environment and provides a highly userfriendly interface. It can be freely downloaded from the following internet addresses: http://www.nscl.msu/edu/lise http://dnr080.jinr.ru/lise Application The program has been developed to calculate the transmission and yields of fragments and fusion residues produced and collected in a spectrometer. LISE++ is the new generation of the LISE code, which allows the creation of a spectrometer through the use of different “blocks”. A “block” can be a dipole (dispersive block), a material, a piece of beampipe, etc. The LISE code may be applied at low-energy, mediumenergy and high-energy facilities (fragment- and recoilseparators with electrostatic and/or magnetic selections). A number of these facilities like A1900 and S800 at NSCL, RIPS at RIKEN, LISE and SPEG at GANIL, FRS at GSI, COMBAS and ACCULINA at Dubna, based on the separation of projectile-like fragments are included or might be easily added to the existing optical configuration files. The LISE code geography Italy 3% Other 18% China 3% France 6% Russia 8% Germ any 9% Japan 13% USA 40% Main features Fast analytical calculations Reaction mechanisms projectile fragmentation, fusion-evaporation, Coulomb fission, Abrasion-Fission Highly userfriendly environment Optics ( «Transport» matrices are used) Ion charge state distribution calculations (4 methods) Range and energy loss in material calculations (4 methods) Contribution of secondary reactions in the target Different selection methods (“Brho”, “Wedge”, velocity, “Erho”) In-built help support In-built powerful tools In action In-Flight Fission High-energy secondary-beam facilities such as RIA, RIBF and GSI provide the technical equipment for a new kind of fission experiment. We need fast predictions of fission fragment intensities. A new model of fast analytical calculation of fission fragment transmission through a fragment separator has been developed in the framework of the LISE++ code. In the development of the fission mechanism in the LISE++ framework it is possible to distinguish the following principal directions: * Production cross-section of fragments * Kinematics of reaction products * Spectrometer tuning to the fragment of interest to produce maximal rate (or purification) Coulomb Fission Deexcitation channels for 238U nuclei at 600 MeV/u excited by a lead target. The solid red curve represents fission decay. The blue dashed line represents 1n-decay channel, black dotted and green dot-dashed curves respectively 2n- and 3n-decay channels. Abrasion-Fission Abrasion-Fission Abrasion-Fission: what is solution? Fission excitation function Three-excitation-energy-region model Partial and total mass distributions of Strontium fission fragments in the reaction 238U(80MeV/u)+Be. Total fission cross-sections of 238U at relativistic energies Total fission cross-sections of 238U at energies between 0.6 and 1 GeV per nucleon. See inset in the figure for details. LISE calculations were done for two prefragment excitation energy values. 13.3 and 27 MeV/dA. 238U(1AGeV) + Pb T.Enqvist et al., Nucl.Phys. A658 (1999) 47-66 238U(1AGeV) +p M.Bernas et al, Nucl.Phys. A725 (2003) 213-253 238U(1AGeV) +p Measured and LISE calculated fission-fragment mean kinetic energies as a function of their proton for the data [Ber03] (238U(1AGeV)+p). 208Pb(1AGeV) +p T.Enqvist et al., Nucl.Phys. A686 (2001) 481-524. 208Pb(1AGeV) +d T.Enqvist et al., Nucl.Phys. A703 (2002) 435-465 Kinematics Selection Two different methods for fission fragment kinematics are available in LISE++: MCmethod and DistrMethod. DistrMethod is the fast analytical method applied to calculate the fragment transmission through all optical blocks of the spectrometer. MCmethod (Monte Carlo) has been developed for a qualitative analysis of fission fragment kinematics and utilized in the Kinematics calculator. LISE++ DistrMethod LISE++ MCmethod After target After dipole 238U(920AMeV)+Pb(5g/cm2)->100Zr Selection 132Sn fragment energy distribution after the second dipole obtained in the reaction 238U(80MeV/u)+Be(80mg/cm2). Two dimensional identification plot for fission fragments without a wedge. Zinc isotopes are selected by a red contour. Two dimensional identification plot for fission fragments using an achromatic Be-wedge (60mg/cm2). 81Zn is selected by a red contour. Secondary Reactions, Optimum target reduced Yield N target I beam Includes the reaction coefficient of losses and the secondary reactions contribution coefficient Optimal target thickness of Tin isotopes produced in the fission of 238U(1AGeV, 1pnA) on a Be-target taking into account secondary reactions’ contributions. Summary Welcome to the LISE site to see details! Register in LISE’s sites to get information about new versions of the code http://www.nscl.msu.edu/lise or http://dnr080.jinr.ru/lise A new model of fast analytical calculation of fission fragment transmission* through a fragment separator has been developed in the framework of the LISE++ code. The LISE++ program has become an important tool for the planning experiments at different laboratories around the world (RIBF,RIA,GSI). The authors thank for the help in developing Coulomb fission model in the program: Matthew Amthor (NSCL/MSU) Brad Sherrill (NSCL/MSU) Michael Thoennessen (NSCL/MSU) Jorge Pereira Conca (NSCL/MSU) Marc Hausmann (NSCL/MSU) Next steps: secondary reactions in wedge, secondary target, RF-kicker, Monte Carlo transmission. Helmut Weick (GSI) and… DOE #DE-FG03-03ER41265 grant * kinematics of fission products, production cross-section of fragments (Abrasion-Fission & Coulomb fission), spectrometer tuning NSF #PHY-01-10253 grant