RT Journal Article T1 Focalizing slow neutron beams at and below micron scales and discussion on BNCT (II) A1 Molina de la Peña, Ignacio A1 Calvo Padilla, María Luisa A1 Álvarez Estrada, Ramón F. AB We studied the propagation of slow neutrons and their waveguiding properties in certain suitable thin films where Ti and Si play a key role, having in mind their possible use in Boron Neutron Capture Therapy (BNCT) of small tumors. In PBSi2017 we presented a general overview and some specific proposals for improved focalization of slow neutrons (at and a bit below one micron, with propagation up to about 1 m. with relatively small attenuation), by omitting a good number of quantitative aspects. The present work, based upon our presentation in PBSi2018, extends our previous proposals in PBSi2017 and provides more quantitative descriptions of part of them. Neutron wavelengths versus characteristic dimensions of the waveguides in our proposals typically require quantum-mechanical analysis: specifically, the description of the confined neutrons by means of propagation modes. The confined propagation of incoming waves along waveguides, the evolution of the resulting propagation modes and related issues are investigated. Those features give rise to computational challenges, depending on the smallness of (neutron wavelengths/characteristic dimensions). Approximate analytical formula is provided for the corresponding quantum-mechanical probability. Numerical estimates and the results of some simulations are presented. Consequences of the latter for BNCT will be discussed briefly. PB Taylor & Francis Ltd SN 1042-6507 YR 2019 FD 2019-06-22 LK https://hdl.handle.net/20.500.14352/13648 UL https://hdl.handle.net/20.500.14352/13648 LA eng NO © 2019 Taylor and Francis GroupM. L. Calvo acknowledges Spanish Ministry of Economy and Competitiveness under Grant TEC2014-57394-P. R. F. Alvarez-Estrada acknowledges the financial support of Project FIS2015-65078_C2-1-P, Ministry of Economy and Competitiveness, Spain. We are grateful to Prof. Clara Vinas for having encouraged that our work (by virtue of the relationship of the proposals in it to BNCT) be communicated to PBSI2018. NO Ministerio de Economía y Competitividad (MINECO) DS Docta Complutense RD 8 abr 2025