(7)Li(p,n)(7)Be is an endothermic reaction and working near its threshold (1.88 MeV) has the adva... more (7)Li(p,n)(7)Be is an endothermic reaction and working near its threshold (1.88 MeV) has the advantage of neutron spectra with maximum energies of about 100 keV, considerably lower than at higher beam energies, or than using other neutron-producing reactions or as for the uranium fission spectrum, relevant for BNCT based on nuclear reactors. With this primary energy it is much easier to obtain the energies needed for treating deep seated tumors by BNCT (about 10 keV). This work studies bombarding energies up to 2.05 MeV, different beam incidence angles and the effect of the undesirable gamma production via the (7)Li(p,γp') (7)Li reaction.
Giant dipole photo-nuclear reactions generated during Linac radiotherapy are of concern due to th... more Giant dipole photo-nuclear reactions generated during Linac radiotherapy are of concern due to the undesirable neutron dose delivered to patients. Nuclear track methodology provides an estimation of gradients of photo-neutrons fields in radiotherapy treatments for 18 MV linear accelerators and it revealed an unexpected behaviour around isocenter. Enhancement effects are observed on absorbed dose due to both scattered photo-neutrons and (γ,n) reactions. Thermal neutrons can give a dose boost if the tumour is loaded with 10B and a new BNCT approach combined with the standard photon field is proposed.
El presente trabajo se enmarca dentro de un proyecto de la Comision Nacional de Energia Atomica p... more El presente trabajo se enmarca dentro de un proyecto de la Comision Nacional de Energia Atomica para el desarrollo en Argentina de la terapia por captura neutronica en boro o BNCT (por Boron Neutron Capture Therapy) basada en aceleradores de particulas. En particular se describe aqui la metodologia seguida para del diseno de una sala de irradiacion de pacientes que, desde el punto de vista del blindaje, se ajuste a los requerimientos de la Autoridad Regulatoria Nuclear Argentina (ARN) en la materia. Con este fin se partio de un blanco de produccion, moderacion y conformacion del haz de neutrones (o BSA por Beam Shaping Assembly), con geometria sencilla y para la reaccion 7Li(p,n)7Be. Considerando este BSA se realizo un estudio por simulaciones Monte Carlo (utilizando el codigo MCNP) de la radiacion de fuga (neutrones y fotones) a traves de las caras del mismo con el fin de disenar un blindaje recubriendo su superficie. Con el BSA recubierto se procedio al diseno de la sala de irradi...
A new ultrahigh-resolution photoemission electron microscope called PEEM3 is being developed and ... more A new ultrahigh-resolution photoemission electron microscope called PEEM3 is being developed and built at the Advanced Light Source (ALS). An electron mirror combined with a much-simplified magnetic dipole separator is to be used to provide simultaneous correction of spherical and chromatic aberrations. It is installed on an elliptically polarized undulator (EPU) beamline, and will be operated with very high spatial
(7)Li(p,n)(7)Be is an endothermic reaction and working near its threshold (1.88 MeV) has the adva... more (7)Li(p,n)(7)Be is an endothermic reaction and working near its threshold (1.88 MeV) has the advantage of neutron spectra with maximum energies of about 100 keV, considerably lower than at higher beam energies, or than using other neutron-producing reactions or as for the uranium fission spectrum, relevant for BNCT based on nuclear reactors. With this primary energy it is much easier to obtain the energies needed for treating deep seated tumors by BNCT (about 10 keV). This work studies bombarding energies up to 2.05 MeV, different beam incidence angles and the effect of the undesirable gamma production via the (7)Li(p,γp') (7)Li reaction.
Giant dipole photo-nuclear reactions generated during Linac radiotherapy are of concern due to th... more Giant dipole photo-nuclear reactions generated during Linac radiotherapy are of concern due to the undesirable neutron dose delivered to patients. Nuclear track methodology provides an estimation of gradients of photo-neutrons fields in radiotherapy treatments for 18 MV linear accelerators and it revealed an unexpected behaviour around isocenter. Enhancement effects are observed on absorbed dose due to both scattered photo-neutrons and (γ,n) reactions. Thermal neutrons can give a dose boost if the tumour is loaded with 10B and a new BNCT approach combined with the standard photon field is proposed.
El presente trabajo se enmarca dentro de un proyecto de la Comision Nacional de Energia Atomica p... more El presente trabajo se enmarca dentro de un proyecto de la Comision Nacional de Energia Atomica para el desarrollo en Argentina de la terapia por captura neutronica en boro o BNCT (por Boron Neutron Capture Therapy) basada en aceleradores de particulas. En particular se describe aqui la metodologia seguida para del diseno de una sala de irradiacion de pacientes que, desde el punto de vista del blindaje, se ajuste a los requerimientos de la Autoridad Regulatoria Nuclear Argentina (ARN) en la materia. Con este fin se partio de un blanco de produccion, moderacion y conformacion del haz de neutrones (o BSA por Beam Shaping Assembly), con geometria sencilla y para la reaccion 7Li(p,n)7Be. Considerando este BSA se realizo un estudio por simulaciones Monte Carlo (utilizando el codigo MCNP) de la radiacion de fuga (neutrones y fotones) a traves de las caras del mismo con el fin de disenar un blindaje recubriendo su superficie. Con el BSA recubierto se procedio al diseno de la sala de irradi...
A new ultrahigh-resolution photoemission electron microscope called PEEM3 is being developed and ... more A new ultrahigh-resolution photoemission electron microscope called PEEM3 is being developed and built at the Advanced Light Source (ALS). An electron mirror combined with a much-simplified magnetic dipole separator is to be used to provide simultaneous correction of spherical and chromatic aberrations. It is installed on an elliptically polarized undulator (EPU) beamline, and will be operated with very high spatial
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