MOCADI_FUSION: Extension of the Monte-Carlo code MOCADI to heavy-ion fusion–evaporation reactions

Fast neutrons (FN) have a higher radio-biological effectiveness (RBE) compared with photons, however the mechanism of this increase remains a controversial issue. RBE variations are seen among various FN facilities and at the same facility when different tissue depths or thicknesses of hardening filters are used. These variations lead to uncertainties in dose reporting as well as in the comparisons of clinical results. Besides radiobiology and microdosimetry, another powerful method for the characterization of FN beams is the calculation of total proton and heavy ion kerma spectra. FLUKA and MCNP Monte Carlo code were used to simulate these kerma spectra following a set of microdosimetry measurements performed at the National Accelerator Centre. The calculated spectra confirmed major classical statements: RBE increase is linked to both slow energy protons and alpha particles yielded by (n,α) reactions on carbon and oxygen nuclei. The slow energy protons are produced by neutrons having an energy between 10 keV and 10 MeV, while the alpha particles are produced by neutrons having an energy between 10 keV and 15 MeV. Looking at the heavy ion kerma from <15 MeV and the proton kerma from neutrons <10 MeV, it is possible to anticipate y* and RBE trends.Key words: fast neutron, kerma, microdosimetry, RBE, Monte Carlo.

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Description and use of the Monte Carlo code LILITA. [Modeling of equilibrium decay of heavy ion reaction products]

10.2172/6281833 ◽

1981 ◽

Cited By ~ 2

Author(s):

J. Gomez del Campo ◽

R. G. Stokstad

Keyword(s):

Monte Carlo ◽

Heavy Ion ◽

Monte Carlo Code ◽

Reaction Products

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Heavy-ion production of 77Br and 76Br

Scientific Reports ◽

10.1038/s41598-021-94922-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Sean R. McGuinness ◽

John T. Wilkinson ◽

Graham F. Peaslee

Keyword(s):

Target Material ◽

Chemical Separation ◽

Heavy Ion ◽

Accelerator Facility ◽

Promising Alternative ◽

Ion Production ◽

Current Production ◽

The University ◽

Heavy Ion Fusion ◽

Fusion Evaporation Reactions

AbstractMany radioisotopes with potential medical applications are difficult to produce routinely, especially those on the proton-rich side of the valley of stability. Current production methods typically use light-ion (protons or deuteron) reactions on materials of similar mass to the target radioisotope, which limits the elemental target material available and may require the use of targets with poor thermal properties (as is the case for the production of radiobromine). These reactions may also create significant amounts of proton-rich decay products which require chemical separation from the desired product in a highly radioactive environment. A promising alternative method using heavy-ion fusion-evaporation reactions for the production of the medically relevant bromine radioisotopes 76Br (t1/2 = 16.2 h) and 77Br (t1/2 = 57.0 h) is presented. Heavy-ion beams of 28Si and 16O were used to bombard natural chromium and copper targets just above the Coulomb barrier at the University of Notre Dame's Nuclear Science Laboratory to produce these bromine and precursor radioisotopes by fusion-evaporation reactions. Production yields for these reactions were measured and compared to PACE4 calculations. In addition to using more robust targets for irradiation, a simple physical–chemical separation method is proposed that will lead to very high radiopurity yields. A summary of accelerator facility requirements needed for routine production of these radioisotopes is also presented.

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