Design of a spectrum syntonizer system by neutron capture boron therapy

Three BNCT facilities were designed in this work: an epithermal facility for a 22 Mwatts-MPR research reactor, and two removable facilities for a 10 Mwatts-MTR type reactor, for thermal and epithermal therapy. Dosimetric and thermal aspects were considered for the design. A characterization of the materials which are usually used to obtain the required neutron spectrum had been done previously. This characterization consisted in a study of the neutrons and photons behavior, and also the behavior of its adjuncts, throw the mentioned materials. Facilities composed by a filter-attenuation section, followed by a collimator-section were designed for both reactors. The filter-section consists in a material block to tune the spectrum, and the collimator-section is a 1m long tube for the MRP, and a 50 cm long cone for the MTR. In the 22 MW reactor, it was obtained a facility of an epithermal neutron intensity of 6.9X108 n/cm2 seg, with a treatment time of 1 hour and a dose due to fast neutrons and photons lower than 20 cGy and 1.2 Gy, respectively. For the 10MW reactor, it was designed an epithermal facility which has an epithermal neutron intensity of 1.9X109 n/cm2 seg, a treatment time of 22 minutes, and a 25 cGy dose due to fast neutrons and 1.25Gy due to photons. The thermal facility designed for this reactor, has a thermal neutron intensity if 5.4X109n/cm2 seg, an irradiation time of 10 minutes, and an absorbed dose lower than 0.5 mGy due to fast neutrons and epithermal neutrons, and lower than 0.4Gy due to photons. (author)