Please use this identifier to cite or link to this item: http://ricaxcan.uaz.edu.mx/jspui/handle/20.500.11845/746
Title: Neutron spectra and H*(10) of photoneutrons inside the vault room of an 18 MV LINAC
Authors: Bañuelos Frías, Alan
Borja Hernández, Candy Gretel
Guzmán García, Karen Arlete
Valero Luna, Claudia
Hernández Dávila, Víctor Manuel
Vega Carrillo, Héctor René
Issue Date: Jun-2012
Publisher: Sociedad Mexicana de Física, A.C.
Abstract: El espectro de neutrones y el equivalente de dosis ambiental fueron estimados dentro de una sala de radioterapia con un Linac de 18 MV. Las estimaciones se llevaron a cabo utilizando m´etodos Monte Carlo donde una sala realista fue modelada incluyendo un fantoma de tejido equivalente. El t´ermino fuente para neutrones fue calculado usando la funci´on de Tosi et al, la cual contabiliza los neutrones de evaporaci´on y reacci´on directa. El espectro fue estimado usando dos diferentes distribuciones de energ´ıa. Los detectores fueron colocados en el plano donde se encuentra el isocentro. Dentro de la sala de tratamiento, como la distancia respecto al isocentro aumenta, la cantidad de neutrones y H*(10) se reduce, los neutrones dentro de la regi´on de alta energ´ıa son desplazados a una regi´on de menor energ´ıa de alrededor de 0.1 MeV. Sin embargo, los neutrones epit´ermicos y t´ermicos permanecen constantes debido al efecto de room-return. En el laberinto el espectro es dominado peor neutrones t´ermicos y epit´ermicos los cuales contribuyen a la producci´on de activaci´on y a la producci´on de rayos gamma prontos.
Description: Neutron spectra and the ambient dose equivalent were estimated inside the radiotherapy hall with an 18 MV linac. Estimations were carried out using Monte Carlo methods where a realist hall was modeled including a phantom made of equivalent tissue. The source term for photoneutrons was calculated using the Tosi et al. function that account for evaporation and knock-on neutrons. The spectra were estimated using two different energy distributions. Detectors were located in several sites inside the hall including the maze and outside the hall door, all detectors were located at the plane were the isocenter is located. In the treatment hall, as the distance respect to the isocenter is increased, the amount of neutrons and the H*(10) are reduced, neutrons in the high-energy region are shifted to lower region peaking around 0.1 MeV, however the epithermal and thermal neutrons remain constant due to the room-return effect. In the maze the spectra are dominated by epithermal and thermal neutrons that contributes to produce activation and the production of prompt gamma-rays.
URI: http://localhost/xmlui/handle/20.500.11845/746
https://doi.org/10.48779/xgzy-a591
ISSN: 0035-001X
Other Identifiers: info:eu-repo/semantics/publishedVersion
Appears in Collections:*Documentos Académicos*-- UA Ciencias Nucleares

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