Target and PADC Track Detectors for Rare Isotope Studies

A higher yield of rare isotope production methods, for example, isotope separation on-line (ISOL), is expected to be developed for the EURISOL facility. In this paper as a part of the ongoing project, high power-target assembly and passive detector inclusion are given. Theoretical calculations of several configurations were done using Monte Carlo code FLUKA aimed to produce 1015 fiss/s on LEU-Cx target. The proposed radioactive ion beam (RIB) production relies on a high-power (4 MW) multibody target; a complete target design is given. Additionally we explore the possibility to employ PADC passive detector as a complementary system for RIB characterization, since these already demonstrated their importance in nuclear interactions phenomenology. In fact, information and recording rare and complex reaction product or short-lived isotope detection is obtained in an integral form through latent track formation. Some technical details on track formation and PADC detector etching conditions complete this study

Radioactivity concentration and heavy metal content in fuel oil and oil-ashes in Venezuela

Environmental radiation levels are modified in regions where the oil industrial activity is more aggressive, such as in the Zulia State and the Orinoco´s Oil Belt. In these regions Venezuela is producing 1750 thousand barrels of oil from the near-to-the-surface or deep oil drilling, being its 2003 total OPEC market share 2932 thousand barrels of oil per day [1]. Petroleum constitutes an important source of energy and as the majority of natural sources it contains radionuclides and their disintegration products. The combustion of oil concentrates in the ashes those radioelements, which later enters the environment by different pathways producing adverse effects on the quality of man life. The concentration of radioelements varies greatly between oil fields, and then still requiring local survey studies in this area. Moreover due to the recent national interest in recycling processes, it becomes important to take care in the selection of materials that may contain by-products of industrial origin. In fact the oil ashes and other mining by-products are employable in the building industry. The concentration of radioactivity and heavy metals in crude oil, fuel oil Nº 6 and the ashes from power plants were determined. The analysis includes the two major thermoelectric power plants in Venezuela, Ricardo Zuluaga on the northern seaside of Caracas and Planta Centro on the littoral of Carabobo State. The study covers different samples: fuel oil No 6, heavy and medium petroleum as well as fuel Oil No6 ashes. Gamma spectrometry was used for measuring 226Ra, 214Pb, 214Bi, 228Ac, 212Pb, 212Bi, 208Tl and 40K, and heavy metallic cations were determined by ICP-MS, which also allows the direct determination of 232Th and 238U. In this material (oil ashes) the total activity concentration is above 300 Bq.kg-1. Some criteria from the literature have been compared and used to investigate the applicability of oil ashes as an additive for building materials. The combustion concentrate also heavy metal cations, as is the case of Pb, Ni, Mn, V, Zn among others. The found high metal concentrations can represent an important environmental risk since the high amount of sulfates in the Venezuelan oil and ashes contributes to their dissolution and bioavailability

Algoritmo matemático eficiente para la resolución, por el método de diferencias finitas, de la ecuación de difusión-advección acoplada a modelos cinéticos de transferencia de seudo-primer orden

Los modelos cinéticos de seudo-primer orden han demostrado su utilidad para estudiar el comportamiento de una gran variedad sustancias: radionúclidos, metales pesados, pesticidas, petróleo, etc., siendo capaces de describir los procesos de intercambio con el sustrato o la retención de fluidos en estructuras porosas. Sin embargo, los modelos hidrodinámicos que incluyen la simulación de dichos procesos, están limitados por las exigencias computacionales que se derivan de resolver simultáneamente la difusión-advección y el transporte reactivo. En este trabajo se presenta un algoritmo que permite realizar éste cálculo reduciendo el tiempo de cómputo (hasta diez mil veces)The pseudo first order kinetic models have shown it usefulness to study the behavior of a great variety of substances: radionuclides, heavy metals, pesticides, oil, etc. These models are able to describe the complex exchange processes with the substrates or the partial retention of fluids in the porous structures. However, the hydrodynamic models which incorporate the numerical simulation of those processes are limited due to the computing exigencies when resolving the diffusion-advection together with the reactive transport. In this work we present an algorithm that allows this calculation reducing the computing time (up to 10 thousand times

The effect of customer perceived value on customer satisfaction: a case study of Malay upscale restaurants

Stiff competition and increasingly high operating costs have driven many international and domestic players to introduce new outlet concepts. Malay fine dining, upscale restaurant segment is gaining popularity among Malaysian, especially in Kuala Lumpur. This study examined the effect of perceived value on customer satisfaction in Malay upscale restaurants in terms of emotional responses, monetary prices, behavioral price and reputation. Primary data were gathered from 170 questionnaires returned by respondents from five Malay upscale restaurants in Kuala Lumpur, and statistically analysed using SPSS version 21. The findings of this study revealed that monetary prices had a high positive relationship with customer satisfaction. In addition, the beta value for emotional responses (β=0.530, p<0.01), behavioral price (β=0.180, p<0.01) and reputation (β=0.168, p<0.01) also indicated the respective contributions made to customer satisfaction

Radiaciones ionizantes y su impacto Primer Simposio Internacional sobre Medioambiente (ISE 2017)

Son ya varias las décadas en las que en América Latina se ha trabajado arduamente sobre las radiaciones ionizantes; tanto en las ionizantes directas, tales como las partículas beta positivas y negativas, las partículas alfa, los protones, los mesones cargados, los muones y los iones pesados, así como también en las ionizantes indirectas (las producidas por partículas sin cargas), como las generadas por fotones con energías superiores a los 10 keV y los neutrones. Por otro lado, las radiaciones no ionizantes también han sido objeto de detallados estudios, y muy especialmente las provenientes del Sol, como el factor natural más influyente sobre la Tierra. En esta obra se presentan algunos de los avances en los que han participado reconocidos científicos latinoamericanos, como el Dr. Héctor Vega Carrillo, Dr. Daniel Palacios, Dra. Patrizia Pereyra, Dra. Sheila Serrano, y el Dr. Manuel Ernesto Delgado, entre otros. Esta obra puede ser de interés para profesionales del área de la protección radiológica, la ingeniería ambiental, física de la atmósfera y áreas afines, así como para estudiantes

Chapter Boron Studies in Interdisciplinary Fields Employing Nuclear Track Detectors (NTDs)

Pollution & threats to the environmen

Chernóbil, una visión global

Se rese&ntilde;an las causas del accidente y los informes sobre la mortalidad causada por el mismo seg&uacute;n reportes cient&iacute;ficamente autorizados emitidos a los 20 a&ntilde;os por el Organismo Internacional de Energ&iacute;a At&oacute;mica (OIEA) y el World Health Organization (WHO) haciendo notar que la mortalidad fue y ha sido exagerada por razones de &iacute;ndole pol&iacute;tica. Para poner en perspectiva el da&ntilde;o debido al accidente se rese&ntilde;an otros desastres como son 1.- las pruebas nucleares realizadas por razones belicistas por USA, USSR, Inglaterra, Francia, China, India, Paquist&aacute;n y Corea del Norte. 2.- El accidente de Bohpal en la India, 3.- La mortalidad debida al uso de carb&oacute;n para generar energ&iacute;a, 4.-El accidente de TACOA y 5.- La mortandad anual por violencia en Venezuela. Dada la demanda mundial por energ&iacute;a el&eacute;ctrica y el actual rechazo al uso del uranio en reactores nucleares, se rese&ntilde;a una alternativa: el reactor de torio de sal fundida que presenta ventajas que resuelven casi todas las causas del rechazo al uso de la energ&iacute;a nuclear

SSNTD Technique in Photo-neutron Applications

Passive Solid State Nuclear Track Detectors (SSNTDs) are a versatile tool for neutron studies as has been shown long ago and several good quality materials are commercially available. They are useful for charged particle detection in the linear energy transfer (LET) range above the threshold value of ~10 keV μm-1. Linacs, operating above 6 MeV up to the energy region where radiotherapy is applied usually up to ~25MeV, induce unwanted photo-neutron field; their spectra shows two components due to reaction dynamics based on evaporation and knock-on mechanisms. Neutrons produced by Linacs are often neglected in health application; however, today it has become necessary to assess the effect on patient, staff and radiation workers. Radiation studies using SSNTDs play a major role in this case. Other fields also take advantage of the passive detectors properties; in fact they are employed with success to measure neutron signals relevant for plasma diagnostics as it was demonstrated at the RFX facility as part of the ITER project. The PADC-NTD techniques provide information on external neutron field values around the RFXinstallation during pulsed operation. In any case, converter materials, as charged particles from (n, p) and (n, α) reactions, are required to produce neutron fingerprints through latent tracks. These once etched provide information on neutron fluence spatial values. Track histograms are then employed to determine photo-neutron induced damage in materials as well as radiation dose to both patient and professionally exposed workers. The estimated neutron fluence that can be determined by NTM covers a large range of values, the largest being above 1010 (± 12%) neutrons/cm2