Characteristics, as a shield against ionizing photons, of concrete blocks used in the construction industry.

INEGI reports that 81% of new constructions are built with durable materials, such as concrete blocks, including rooms where ionizing radiation is used, such as clinics and hospitals. The volume ratios used in the manufacture of concrete blocks have a 1: 5: 2 ratio of: portland cement, sand and crushed gravel. The percentage mass content of each atom in the sample is obtained with the energy-dispersed X-ray fluorescence, these results are used to calculate the characteristics such as shielding of the concrete blocks, which have been partially reported, in this work several characteristics are presented for photons from 1 keV to 100 GeV, such as linear attenuation coefficients, the hemireductive layer, the effective, atomic and electronic sections, the effective atomic number (Zef). The exposure of accumulation and energy absorption factors (EBF, EABF) of 0.5-40 mfp are reported, using the Photon Shielding and Dosimetry (PSD) software. These characteristics are compared to those of NBS concrete. The concrete blocks have an attenuation capacity for energies used in radiological equipment such as mammography, 20-35 keV; dental, 50-90 keV and for conventional radiography equipment, 70-150 keV, so the block and lightened concrete block must be considered in the calculations of primary and secondary shielding walls.

Radiation shielding and dosimetric parameters of mexican artisanal bricks.

In this work, were determined some radiation shielding and dosimetric parameters of three types of bricks for photons energy from 1 keV to 100 GeV photons using the Phy-X/PSD software, and for comparison also has been calculated the same parameters for NBS concrete. The parameters calculated are the linear attenuation coefficients (LAC), effective atomic numbers (Zeff), half value layers (HVL), the energy absorption buildup factors (EABF) and the exposure buildup factors (EBF), as well as the coefficients to use the geometric progression (G-P) fitting method. Obtained results show that the three types of bricks can be used safely for the design of medical facilities housing mammography units (less than 30 keV).

Induced radioisotopes in a linac treatment hall.

When linacs operate above 8MV an undesirable neutron field is produced whose spectrum has three main components: the direct spectrum due to those neutrons leaking out from the linac head, the scattered spectrum due to neutrons produced in the head that collides with the nuclei in the head losing energy and the third spectrum due to room-return effect. The third category of spectrum has mainly epithermal and thermal neutrons being constant at any location in the treatment hall. These neutrons induce activation in the linac components, the concrete walls and in the patient body. Here the induced radioisotopes have been identified in concrete samples located in the hall and in one of the wedges. The identification has been carried out using a gamma-ray spectrometer.