D. Scannicchio

The FLUKA code: an overview

FLUKA is a multipurpose Monte Carlo code which can transport a variety of particles over a wide energy range in complex geometries. The code is a joint project of INFN and CERN: part of its development is also supported by the University of Houston and NASA. FLUKA is successfully applied in several fields, including but not only, particle physics, cosmic ray physics, dosimetry, radioprotection, hadron therapy, space radiation, accelerator design and neutronics. The code is the standard tool used at CERN for dosimetry, radioprotection and beam-machine interaction studies. Here we give a glimpse into the code physics models with a particular emphasis to the hadronic and nuclear sector.

Carbon induced reactions at low incident energies

Accurate knowledge of the reactions which occur when two heavy ions interact is of importance in many trans-disciplinary fields, particularly in cancer therapy and space radiation protection. In these cases one needs to know what happens in a natural process to which all possible reaction mechanisms contribute and thus a theoretical calculation, to be really usable, must indeed be able to reproduce large sets of data in wide energy and mass ranges. We show here the results of an analysis of the spectra of intermediate mass fragments produced in the C + Al interaction at 13 MeV/n, both in direct and inverse kinematics, which supplies a very reasonable reproduction of a great number of data providing useful information on the leading reaction mechanisms.

Update On the Status of the FLUKA Monte Carlo Transport Code

The FLUKA Monte Carlo transport code is a well-known simulation tool in High Energy Physics. FLUKA is a dynamic tool in the sense that it is being continually updated and improved by the authors. We review the progress achieved since the last CHEP Conference on the physics models, some technical improvements to the code and some recent applications. From the point of view of the physics, improvements have been made with the extension of PEANUT to higher energies for p, n, pi, pbar/nbar and for nbars down to the lowest energies, the addition of the online capability to evolve radioactive products and get subsequent dose rates, upgrading of the treatment of EM interactions with the elimination of the need to separately prepare preprocessed files. A new coherent photon scattering model, an updated treatment of the photo-electric effect, an improved pair production model, new photon cross sections from the LLNL Cullen database have been implemented. In the field of nucleus-- nucleus interactions the electromagnetic dissociation of heavy ions has been added along with the extension of the interaction models for some nuclide pairs to energies below 100 MeV/A using the BME approach, as well as the development of an improved QMD model for intermediate energies. Both DPMJET 2.53 and 3 remain available along with rQMD 2.4 for heavy ion interactions above 100 MeV/A. Technical improvements include the ability to use parentheses in setting up the combinatorial geometry, the introduction of pre-processor directives in the input stream. a new random number generator with full 64 bit randomness, new routines for mathematical special functions (adapted from SLATEC). Finally, work is progressing on the deployment of a user-friendly GUI input interface as well as a CAD-like geometry creation and visualization tool. On the application front, FLUKA has been used to extensively evaluate the potential space radiation effects on astronauts for future deep space missions, the activation dose for beam target areas, dose calculations for radiation therapy as well as being adapted for use in the simulation of events in the ALICE detector at the LHC.

Role of DNA organisation and environmental scavenging capacity in the evolution of radiobiological damage: models and simulations

BACKGROUND AND PURPOSE Theoretical models and Monte Carlo simulations were developed, aimed to investigate the role played by the organisation of interphase DNA and the environmental scavenging capacity conditions in the induction of radiobiological damage. METHODS The induction of single- and double-strand breaks by gamma rays impinging on different DNA structures (e.g. linear DNA, SV40 minichromosome and cellular DNA) was simulated as a function of the environment scavenging capacity. Furthermore, yields of chromosome aberrations (CA) induced by gamma rays and light ions were simulated with a purposely developed MC code that explicitly takes into account the DNA higher-order organisation as chromosome territories. RESULTS AND CONCLUSIONS Simulations performed with the PARTRAC code allowed quantification of the dependence of dsb and ssb both on the target structure, and on the scavenging capacity. The results relative to CA showed the importance of DNA damage complexity (nanometre scale) and interphase chromosome domains (micrometre scale) in the process of aberration formation. Very good agreement was found between the model predictions on ssb, dsb and CA and available experimental data.

FLUKA status and preliminary results from the July-2005 AGS run

As reported in 2005 Aerospace Conference, the FLUKA Monte Carlo code is being modified as part of NASAs Space Radiation Shielding Program for use in simulating the space radiation environment, in order to evaluate the properties of spacecraft and habitat shielding. Since the last workshop, several notable enhancements have been made to the FLUKA code itself and the ancillary support software. These include improvements to the GUI-based packages for analysis of the results as well as GUI-based tools to ease the setup and running of the programs. Examples of these are presented. From the physics perspective, an accelerator run this July at the AGS was undertaken in collaboration with the groups from LBL and MSFC to measure the fragmentation, neutron and secondary charged particle spectra from Fe, Si and C beams at 3, 5 and 10 GeV/A on a variety of targets including C, Al, Fe, Cu and polyethylene. This energy range is the crossover point in event generator technique and the data help guide the evolution of the event generators in this crucial region. Preliminary results from this run is presented for the angular distribution of the secondary charged particles from scattering angles of 3-45 degrees along with normalized comparisons to RQMD and DPMJET, the event generators that are currently employed within FLUKA

Event generators for simulating heavy ion interactions to evaluate the radiation risks in spaceflight

Simulating the space radiation environment with Monte Carlo codes, such as FLUKA, requires the ability to model the interactions of heavy ions as they penetrate spacecraft and crew members bodies. Monte-Carlo-type transport codes use total interaction cross sections to determine when a particular type of interaction has occurred. Then, at that point, a distinct event generator is employed to determine separately the results of that interaction. The space radiation environment contains a full spectrum of radiation types, including relativistic nuclei, which are the most important component for the evaluation of crew doses. Interactions between incident protons with target nuclei in the spacecraft materials and crew members bodies are well understood. However, the situation is substantially less comfortable for incident heavier nuclei (heavy ions). We have been engaged in developing several related heavy ion interaction models based on a quantum molecular dynamics-type approach for energies up through about 5 GeV per nucleon (GeV/A) as part of a NASA consortium that includes a parallel program of cross section measurements to guide and verify this code development