Ionization of short-lived isotopes in a hot cavity – Numerical simulations

Calculations of Ion Beam Emittance for Hot Cavity Ion Source

“…A particle could be ionized/neutralized at the hot ionizer surface with probability given by the ionization coefcient β, see [12] for details. Nuclides produced in the ion source undergo radioactive decay, hence each test particle is assumed to transform from primary to secondary nuclide after some time t dec determined using the Monte Carlo approach…”

“…A lot of analytical models were developed over decades ([911], see also references in [12]). Some attempts were made in order to describe diusion of nuclides in target and eusion in the surface ion sources [1315].…”

“…Some attempts were made in order to describe diusion of nuclides in target and eusion in the surface ion sources [1315]. Recently, a numerical model of ionization in hot cavity ion source has been developed [12,16,17], taking into account not only surface ionization but also possible eects of electron impact ionization mechanism [18]. Initially the model was suitable for stable and long-lived isotopes, but radioactive decay and delays due to the diusion and eusion were implemented [12,19], making it useful also for short-lived isotopes, which are common in on-line nuclear spectroscopy.…”

“…Recently, a numerical model of ionization in hot cavity ion source has been developed [12,16,17], taking into account not only surface ionization but also possible eects of electron impact ionization mechanism [18]. Initially the model was suitable for stable and long-lived isotopes, but radioactive decay and delays due to the diusion and eusion were implemented [12,19], making it useful also for short-lived isotopes, which are common in on-line nuclear spectroscopy. Mainly tubular cavities were considered, but the model was extended to spherical cavities [20], which are employed in experiments [21,22].…”

Ionisation Efficiency in Conical Hot Cavities

“…Electron impact ionisation was also proven to bring very important contribution for high ioniser temperatures and in the case of hard-to-ionise elements [14]. Several modifications were made to take into account radioactive decay of nuclides and delays due to the diffusion out of the target as well as effusion delay (related to sticking of particles to the ioniser walls) [15,16]. The model enabled studies of ion source efficiency as a function of many factors, like ioniser temperature, extraction voltage, timescales governing diffusion and effusion processes, as well as radioactive decay half-life.…”