h. hadizadeh

In radiation therapy with ion beams, lateral distributions of absorbed dose in the tissue are important. Heavy ion therapy, such as carbon-ion therapy, is a novel technique of high-precision external radiotherapy which has advantages over proton therapy in terms of dose locality and biological effectiveness. In this study, we used Monte Carlo method-based Geant4 toolkit to simulate and calculate the effects of energy, shape and type of ion beams incident upon water on multiple scattering processes. Nuclear reactions have been taken into account in our calculation. A verification of this approach by comparing experimental data and Monte Carlo methods will be presented in an upcoming paper. Increasing particle energies, the width of the Bragg curve becomes larger but with increasing mass of particles, the width of the Bragg curve decreases. This is one of the advantages of carbon-ion therapy to treat with proton. The transverse scattering of dose distribution is increased with energy at the end of heavy ion beam range. It can also be seen that the amount of the dose scattering for carbon-ion beam is less than that of proton beam, up to about 160mm depth in water. The distortion of Bragg peak profiles, due to lateral scattering of carbon-ion, is less than proton. Although carbon-ions are primarily scattered less than protons, the corresponding dose distributions, especially the lateral dose, are not much less.

Barandagh quadrangle is located in northeast of Zandjan, and is a part of polymetallic region of Tarem-Zandjan. Field evidence and microscopic studies show an intimate relationship between geochemical anomalies and alteration zones in this area. Based on the field observations and mineralogical studis, these zones, in light of extent, locality, and constituent mineral assemblage, differ from one another, and are scattered along the main shear zone of the area and the margin of Ghezel-Ozan river. The major alteration zones in this area are affiliated with the shear zone, and can be categorized into two discrete alteration types: 1) hypogene acid-sulfate (e.g., silicified, alunitized, advanced argillic, sericitic, and propylitic zones) and 2) supergene acid-sulfate (characterized by minerals assemblage such as jarosite, alunite, goethite, gypsum, and native sulfur). Alteration zone along the margin of Ghezel-Ozan river consists of neutral-pH types of alterations (consisting mainly of argillic, calc-silicate-bearing, and zeolitic zones). In general, these alteration zones were developed by the function of a vast geothermal system during the late Oligocene to Mid-Miocene time. Date gathered indicate that the discrepancy in reaction rate between the fluids and the enclosing rocks caused the development of these two types of alterations. Note the type of alteration zones and the obtained results from geochemical exploration, show that this area possesses suitable potential for prospecting of Ag-Au epithermal and polymetallic (Cu, Pb, Zn, Au, Ag) deposits.