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LISE++ development : application to Coulomb fission

LISE++ development : application to Coulomb fission. The code operates under MS Win-dows environment and provides a highly user-friendly interface. It can be freely downloaded from the fol-lowing internet addresses: http://www.nscl.msu/edu/lise http://dnr080.jinr.ru/lise. Introduction.

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LISE++ development : application to Coulomb fission

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  1. LISE++ development : application to Coulomb fission The code operates under MS Win-dows environment and provides a highly user-friendly interface. It can be freely downloaded from the fol-lowing internet addresses: http://www.nscl.msu/edu/lise http://dnr080.jinr.ru/lise

  2. Introduction Application The program 1)  has been developedto calculate the transmission and yields of fragments and fusion residues 2)produced and collected in a spectrometer. This code allows to simulate an experiment, beginning from the parameters of the reaction mechanism and finishing with the registration of products selected by a spectrometer. An application of transport integral3) lies in the basis of fast calculations of the program for the estimation of temporary evolution of phase space distributions. 1) D.Bazin, M.Lewitowicz, O.Sorlin, O.Tarasov, Nucl.Instr. and Meth. A 482 (2002) 314. O.B.Tarasov, D.Bazin,  M.Lewitowicz, O.Sorlin ,Nuclear Physics A  701 (2002)  661-665.  2) O.Tarasov and D.Bazin, NIM B 204 (2003) 174-178. 3) D.Bazin and B.Sherrill, Phys.Rev.E50 (1994) 4017-4021. The LISE code may be applied at low-energy, medium-energy and high-energy facilities (fragment- and recoil-separators with electrostatic and/or magnetic selections). A number of these facilities, like LISE3, SISSI/LISE3 and SPEG at GANIL, FRS at GSI, COMBAS and ACCULINA at Dubna, A1900 and S800 at NSCL, and RIPS at RIKEN, based on the separation of projectile-like fragments are included or might be easily added to the existing optical configuration files. 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 (i.e. a given thickness for a detector), a piece of beampipe, etc. Number of blocks in the spectrometer is limited by operating memory of Your PC and Your imagination

  3. Main features • Fast analytical calculations(Monte Carlo method is applied just for two-dimensional plots • Highly user­friendly environment • Reaction mechanismsprojectile fragmentation, fusion-evaporation, Coulomb fission(fusion-fission & abrasion-fission under construction) • Optics ( «Transport» matrices are used) • Ion charge state distributioncalculations (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

  4. In action

  5. Examples: dE-TKE plot

  6. Coulomb Fission High-energy secondary-beam facilities such as GSI, RIA, and RIBF provide the technical equipment for a new kind of fission experiment. 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. Using the LISE code now we can establish the parameters for the RIA fragment separator (see the next talk) . In the development of Coulomb fission in the LISE++ framework it is possible to distinguish the following principal directions: * Kinematics of reaction products; * Production cross-section of fragments * Spectrometer tuning to the fragment of interest to produce maximal rate (or purification).

  7. References: 2) P.Armbruster et al., Z.Phys.A355 (1996) 191. 1) J.Benlliure et al.,Nucl.Phys. A628 (1998) 458. 3) M.Bernas, et al., Nucl.Phys.A725 (2003) 213. Fission fragment kinematics at intermediate and high energies The kinematics of the fission process is characterized by the fact that the velocity vectors of the fission residues populate a narrow shell of a spherein the frame of the fissioning nucleus. The radius of this sphere Vf is defined by the Coulomb repulsion between both fission fragments. In the case of reactions induced by relativistic heavy ions, the transformation into the laboratory frame leads to an ellipsoidal distribution which will characterize the angular distribution of fission residues [1,2] (see Figure). Two different methods for fission fragment kinematics are available in LISE++: MCmethod and DistrMethod. DistrMethodis 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. Fig.a) Schematic view of the experimental parameters shaping the measured velocity spectrum in the frame of the fissioning system. Vf the fission-fragment velocity. b) Velocity spectrum of 128Te in the frame of the fissioning system. The velocity V = 0 refers to the projectile frame 3).

  8. Fission kinematics by Monte Carlo method All reaction settings (projectile, target, setting fragment) and excitation energies can be entered in the “Kinematics calculator” dialog. In the “2D fragment plot” dialog (see Figure) it was possible to set: The energy, horizontal and vertical angular emittances; The angular acceptance shape; The horizontal and vertical angular values and their variance; The center of energy silts and their size in %. Fig. The “2D fragment plot” dialog. Initial excitation energy of fissioning nucleus 238U is equal to 50 MeV

  9. 2D-plots Ax(horizontal component of the angle in the laboratory frame) versus Energy per nucleon of 132Sn final fragment after 238U(600MeV/u) fission. Angular acceptances H=60mrad and V=20mrad. The left picture represents case of using target thickness (Pb 4mm ), the right plot was got in the case of a zero thickness target. Initial excitation energy of fissioning nucleus 238U is equal 50 MeV. Fission kinematics by Monte Carlo method

  10. Fission kinematics by LISE analytical “Distribution” method The Monte Carlo method is a powerful tool for modeling, but sometimes the amount of time spent to get enough statistics makes it more beneficial to use fast analytical methods. The forward “intensity” matrix after cutting by a horizontal rectangle shape acceptance equal to 12 mrad. The forward“energy” matrix.

  11. Spectrometer settings in the case of fission The two new settings mode (“left peak” and “right peak”) have been developed for the case of fission reactions (see screen-shot of the dialog). The default method to tune the spectrometer in the fission case is “right peak” (as on more intense peak). Figure. Horizontal spatial selection of fission fragments by the slits S1. The spectrometer is set to the right peak of 130Te momentum distribution.

  12. Projections (Comparison of different calculation methods) LISE++ DistrMethod LISE++ MCmethod MOCADI

  13. Coulomb fission fragment production cross-sections References 1. J.Benlliure et al., Nuclear Physics A 628 (1998) 458-478. 2. O.Tarasov and D.Bazin, NIM B204 (2003) 174-178. 3. M.G.Itkis et al., Yad.Fiz. 43 (1986) 1125. 4. M.G.Itkis et al., Fiz.Elem.Chastits At.Yadra 19 (1988) 701.

  14. Electromagnetic excitation A well-known review of the processes generated by the electromagnetic interaction in relativistic nuclear, and atomic collisions, by C.Bertulani and G.Baur [Physics Report 163 (1988) 299-408] has been used to obtain the excitation energy function for fission. Differential cross-sections of GDR (red solid curve), GQR(IS) (blue dashed curve), and GQR(IV) (black dot curve) excitations in 238U as calculated from the equivalent photon spectrum representing a 208Pb projectile nucleus at 600 MeV/u.

  15. Deexcitation channels 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.

  16. A semi-empirical model of the fission-fragment properties A semi-empirical model of the fission-fragment properties Figure. LISE’s calculation of potential energy at the fission barrier for 238U, as a function of mass asymmetry expressed by the neutron number. References [Ben98] J.Benlliure et al., Nuclear Physics A 628 (1998) 458-478. [Itk86] M.G.Itkis et al., Yad.Fiz. 43 (1986) 1125. [Itk88] M.G.Itkis et al., Fiz.Elem.Chastits At.Yadra 19 (1988) 701.

  17. LISE’s plots for “Coulomb fission” mode Cross Sections Calculated fission fragment differential cross sections for the fissile nucleus 238U for excitation energies: left 12 MeV, right 80 MeV. The total fission cross-section is normalized to 10 mb.

  18. LISE’s plots for “Coulomb fission” mode Total Kinetic Energy Calculated kinetic energies of both final fragments for the fissile nucleus 238U for excitation energies: left 15.4 MeV, right 80 MeV.

  19. LISE’s plots for “Coulomb fission” mode Number of emitted nucleons (dA,dN,dZ) Calculated number of emitted nucleons from one excited fragment for the fissile nucleus 238U excitation energies: left 15.4 MeV, right 80 MeV. Now you don’t need any semi-empirical systematic!

  20. Comparisons with experimental data Cross Sections Experimental production cross-section of cesium isotopes (black squares) with a uranium beam (1GeV/u) in a lead target [Enq99]. Cross sections calculated with the TXE method to set 1 (“Qvalue”). See details on plots. Fragmentation parameterization EPAX2.15 is shown by blue dotted-dash line. [Enq99] T. Enqvist et al., Nucl.Phys. A658 (1999) 47-66.

  21. Comparisons with experimental data Total Kinetic Energy The total kinetic energy as a function of the nuclear charge of the fission fragments. Experi-mental (black circles) values of every element correspond to fission of 233U having passed the lead target at 420 MeV/u [Sch00]. Calculations were done the excitation energy equal to 13.1 MeV what corresponds to the average energy of the EM fission excitation function in the reaction 233U(420 MeV/u)+ Pb. See details for calculated curves in plots [Sch00] K.-H.Schmidt et al., Nucl.Phys. A665 (2000) 221-267.

  22. Thank You for Your attention and Welcome in the LISE site to see details! Register in LISE’s sites to get informationabout new versions of the codehttp://www.nscl.msu.edu/liseor http://dnr080.jinr.ru/lise The authors thank for the help in developingCoulomb fission model in the program: Carlos Bertulani (NSCL/MSU) Alexandra Gade (NSCL/MSU) Brad Sherrill (NSCL/MSU) Michael Thoennessen (NSCL/MSU) Mikhail Itkis (FLNR/JINR, Dubna) Valery Zagrebaev (FLNR/JINR, Dubna) J.Benlliure (University of Santiago de Compostela) Helmut Weick (GSI) and… DOE and NSF grants

  23. In-built tools • Physical Calculator • Nuclide Database utilities • Relativistic Reaction Kinematics Calculations • Curved degrader calculation • PACE4 –evaporation Monte Carlo code for Windows • The spectrometric handbook of J.Kantele & Units converter • Codes “Global” & “Charge” (charge state distributions) • Range optimization utility • “Brho” analyzer • Transport envelope packet package • “Evaporation” calculator • Automatical search of two-dimensional peaks in experimental spectra • LISE for Excel next

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