h. ghods

Following the successful design and construction of a 150keV accelerator tube, the construction of a 200keV electrostatic accelerator system at the Physics Department of the Nuclear Science Research School has been completed. This accelerator includes a 200keV accelerator tube, a high voltage power supply capable of supplying 200kV at 10mA current and a 200kV isolating transformer. An RF type ion source with a system for the control of ion beam could provide ions to the accelerator system. The vacuum system employed is a turbo molecular pumping system coupled with a mechanical rotary pump, where they can provide clean vacuum in the order of 7-10 Torr. In this paper the design criteria and some technical details of the construction of the accelerator system are presented. The construction of this accelerator provides a useful tool for research in various fields and gives an opportunity for the Iranian industry to develop and build accelerator components such as RF, vacuum and accelerator control systems.

Fast neutron flux (14.8 MeV) of a neutron generator has been measured by activation technique. The measurements performed using Cu and Ni threshold detectors. 62Cu and 57Ni were produced through 63Cu (n, 2n) 62Cu and 58Ni (n, 2n)57Ni reactions. They decay by emitting 511 keV and 1377 keV gamma rays, respectively. The half life of 62Cu is 9.74min and that of 57 Ni is 36 hours. The flux of neutron has been calculated by measuring the activity after the irradiation time. Gamma spectroscopy of the activated foils was performed using a HPGe detector. By employing this technique the neutron flux of 2.64×107±3%n/s was obtained for 60 μΑ deuteron of 110 keV energy, bombarding a solid target of 3H.

Batch experiments were conducted to study the ability of marine algae collected from Oman Gulf, Iran, for sorption of cobalt from the metal nitrate solution. The biosorption experiments were performed using native and chemically pretreated sun-dried biomass of marine algae. Our finding indicated that MgCl2 pretreated Cystoseria indica, Sargassum glaucescens and Padina australis had more sorption capacities, while the CaCl2 pretreated ones showed lower capacity (comparing with non-treated native biomass). Also, a fall in the cobalt uptake capacity of Nizimuddinia zanardini, Gracilaria corticata, G. arcuata, Botryocladia leptopoda, Scinaia carnosa, Hypnea valentiae, Ulva fasciata and Codium sp. took place after treatment with chemicals, including CaCl2 (0.1 M), MgCl2 (0.1 M), CaCl2 (0.1 M)/HCl (pH 2) and HCl (0.1 M). Biosorption of cobalt was rapidly took place onto algal biosorbents and most of the sorbed metal ion was bound in the first minutes of contact. Uptake of cobalt was pH-dependent and the most cobalt removal occurred at pH 4. In our screening investigations, brown algae (Dictyota indica, N. zanardini, P. australis, S. glaucescens, and C. indica) removed cobalt most efficiently from aqueous solution, respectively. The capability of marine algae for separation of 60Co was tested and a high 60Co removal was demonstrated.