The FLUKA FLUKA code for space applications: recent developments V. Andersen a , F. Ballarini b , G. Battistoni c , M. Campanella c , M. Carboni d , F. Cerutti c , A. Empl a , A. Fass o e,1 , A. Ferrari e,c, * , E. Gadioli c , M.V. Garzelli c , K. Lee a , A. Ottolenghi b , M. Pelliccioni d , L.S. Pinsky a , J. Ranft f , S. Roesler e , P.R. Sala g,c , T.L. Wilson h a Houston University, Texas, USA b University of Pavia and INFN, Italy c University of Milan and INFN,Via Celoria 16, 20133 Milan, Italy d Laboratori Nazionali di Frascati, INFN, 00044 Frascati, Italy e CERN, Geneva 23, CH-1211, Switzerland f Siegen University, Germany g ETH Zurich, Switzerland h NASA/JSC, USA Received 15 October 2002; received in revised form 27 March 2003; accepted 30 March 2003 Abstract The FLUKA FLUKA Monte Carlo transport code is widely used for fundamental research, radioprotection and dosimetry, hybrid nuclear energy system and cosmic ray calculations. The validity of its physical models has been benchmarked against a variety of experi- mental data over a wide range of energies, ranging from accelerator data to cosmic ray showers in the earth atmosphere. The code is presently undergoing several developments in order to better fit the needs of space applications. The generation of particle spectra according to up-to-date cosmic ray data as well as the effect of the solar and geomagnetic modulation have been implemented and already successfully applied to a variety of problems. The implementation of suitable models for heavy ion nuclear interactions has reached an operational stage. At medium/high energy FLUKA FLUKA is using the DPMJET DPMJET model. The major task of incorporating heavy ion interactions from a few GeV/n down to the threshold for inelastic collisions is also progressing and promising results have been obtained using a modified version of the RQMD RQMD-2.4 code. This interim solution is now fully operational, while waiting for the development of new models based on the FLUKA FLUKA hadron–nucleus interaction code, a newly developed QMD code, and the im- plementation of the Boltzmann master equation theory for low energy ion interactions. Ó 2004 COSPAR. Published by Elsevier Ltd. All rights reserved. Keywords: FLUKA FLUKA code; Space applications; Monte Carlo transport 1. Introduction FLUKA FLUKA (Fass o et al., 2001a,b) is a transport and in- teraction Monte Carlo code, capable of handling ha- dronic and electromagnetic showers from thermal neutrons up to very high energies (100 TeV). Being based, as far as possible, on well tested microscopic models, it ensures a high level of accuracy and versa- tility, it preserves correlations within interactions and among the shower components, and it provides predic- tions where no experimental data is directly available. When needed, powerful biasing techniques are available to reduce computing time. Descriptions of FLUKA FLUKA models and extensive benchmarking can be found in the literature (see the web page, www.fluka.org). FLUKA FLUKA is already widely used for cosmic ray related calculations. Two recent, important examples are the calculation of atmospheric neutrino fluxes (Battistoni et al., 2000), and the evaluation of aircraft exposure (Ferrari et al., 2001; Roesler et al., 2002). A vast amount of benchmarking with muon, hadron and electron data * Corresponding author. Tel.: +41-22-767-6119; fax: +41-22-767- 7555. E-mail address: alfredo.ferrari@cern.ch (A. Ferrari). 1 Present address: SLAC, USA. 0273-1177/$30 Ó 2004 COSPAR. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.asr.2003.03.045 Advances in Space Research 34 (2004) 1302–1310 www.elsevier.com/locate/asr