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The two-step process that characterizes the intermediate-and high-energy photonuclear reactions (between 40 MeV and 4 GeV) has been successfully described by Monte Carlo calculations. Recently, a new class of codes capable to perform those calculations according to a more realistic method has been developed, improving the possibilities for simulating the reactions in more details. In this work we present the CRISP package (standing for Rio-São Paulo Collaboration), which is a coupling of the multi collisional Monte Carlo (MCMC) and the Monte Carlo for evaporation-fission (MCEF) codes. The first one describes the intranuclear cascade process, while the second one is dedicated to the evaporation/fission competition step. Both codes have already shown to be useful for calculating several features of different nuclear reactions. The CRISP code, coupling these two software, represents a good tool to describe the complex characteristics of the nuclear reactions, and opens the opportunity for applications in quite different fields, such as studies of hadron physics inside the nucleus, specific nuclear reactions, spallation and/or fission processes initiated by different probes and many others.

The observed alpha decay half-life values of favoured alpha transitions of ℓ = 5 in bismuth isotopes have been analysed in the framework of a model based on quantum mechanical tunnelling through a potential barrier where the centrifugal and overlapping effects are taken into account. In particular, the very recently measured alpha decay half-life value of (1.9 ± 0.2) × 1019 y for the unique naturally occurring 209Bi isotope has been reproduced by the present approach as (1.0 ± 0.3) × 1019 y. Also, the partial alpha decay half-lives for a number of unmeasured alpha transitions of ℓ = 5 in bismuth isotopes are predicted by the model, thus making it possible to demonstrate the influence of the 126 neutron shell closure on the alpha decay half-life. The present approach is shown to be successfully applicable to other isotopic sequences of alpha-emitter nuclides.

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A semiempirical model based on the quantum-mechanical tunnelling mechanism of alpha emission from nuclei has been used to systematize the alpha-decay half-lives of a set of 336 nuclides, comprising all the alpha-emitter nuclides whose T1/2α-data for ground-state to ground-state transitions of mutual angular momentum ℓ = 0 are known. With a minimum of data rejection (only ∼5% of cases), the procedure has been successful in reproducing quite satisfactorily (within a factor of ∼2) most of the cases (∼80%) investigated. A few significant discrepancies found between measured and calculated results are analysed and discussed. Also reported is the prediction from the model for possible new alpha-emitter nuclides, namely 180W, 184Os and 228Ra, for which cases the calculated partial alpha-decay half-lives fall within the range of half-lives measurable by the current techniques.