A method has been developed to purify bulk amounts of natural thorium from its daughter products. The method is based on anion exchange separation of Th from Pb, Bi, Tl, Ra using Dowex 1 X 8 anion exchange resin conditioned to 2M HCl. The method has several advantages over other methods, namely the decontamination is quite high, Th separation is quantitative and it is suitable for the purification of bulk amounts of Th in a reasonably short time.
Isomer ratios for87Y,86Y and84Rb from -induced reactions on85Rb in the energy range between 20 and 60 MeV have been measured. The data show a characteristic increase followed by a decrease with the increase in bombarding energy. The fall in the isomer ratio values are explained on the basis of enhanced angular momentum depletion by the precompound particles and thereby leaving the compound system at low angular momentum states. A different reaction mechanism has been proposed for the low yield of the high spin isomer in the /, n/ reaction in85Rb.
The absorption behavior of Te and Sb in different oxidation states by anion exchange resins in hydrochloric acid medium has
been studied. Distribution coefficients for Te(IV), Te(VI) as a function of HCl acid concentration (upto 3M HCl) have been
determined. The absorbability for Sb(III) was noticed to be very high and could not be eluted out of the column using HCl
as eluent. Sb(V) could be eluted quantitatively using 3M HCl. The present study clearly indicate that due to the EC/β+ decay of the parent isotopes117,118Te, the daughter nuclei117,118Sb are produced predominantly as Sb(III).
A method for the separation of carrier-free arsenic from bulk amount of germanium has been developed.74,73As has been produced through the reactionnatGe(p,xn)47,73As with 13 MeV protons obtained from Variable Energy Cyclotron, Calcutta. The separation is performed by the distillation
of Ge followed by anion exchange separation of As(V) using Dowex 1×8 anion exchange resin. The overall chemical yield is found
to be (87±3%).
Hafnium ion forms a strong complex with nitrilotriacetic acid (NTA). But there is a controversy about the nature of the complex on whether it is a 1:1 or a 1:2 complex. We have carried out an electrophoresis experiment and supplemented data to establish the nature of the complex. Our data indicates that it is a 1:2 complex i.e. [Hf(NTA)2]2- in which the coordination number 8 has been satisfied for hafnium.
Complexes of Hf with polyaminopolycarboxylic acids viz. diethylene-triamine-penta-acetic acid (DTPA) and its dimethoxy derivative DMDTPA have been studied using paper chromatography at different acidities. Kinetic stabilities of the complexes have also been looked at. Behaviors of these two ligands in complexing with Hf(IV) have been found to be similar. The extent of complexation reduces slowly with acidity and increase with time and reaches a maximum around 70-80% after about 24 hours.
A method for the separation of carrier-free vanadium from scandium and bulk amount of titanium has been developed. Vanadium has been produced through the reactionnatTi(d,n)48,49V with 8 MeV deuterons from the Variable Energy Cyclotron, Calcutta. The separation is performed with Dowex 1×8, 50–100 mesh fluoride from anion exchange resin which retains all the scandium and titanium with 4.5M hydrofluoric acid as eluent, while vanadium(V) is easily eluted. The chemical yield of vanadium was >85%.
Authors:R. Guin, S. Saha, S. Sahakundu and Satya Prakash
The decay of 33 min 2+ isomeric state of104Ag has been studied.104Ag has been produced following the103Rh(, 3n) and107Ag(, 3n) reactions using 29 and 55 MeV -particles, respectively. The present results indicate that104mAg decays mainly by EC/
+ decay. The IT branch for this decay was found to be <0.07% as against the reported value of 33±5%.
Authors:A. Mohanty, S. Das, K. Van, D. Sengupta and S. Saha
The beach placer deposit at Chhatrapur coast of Orissa state, southeastern coast of India, has a significant concentration of radiogenic heavy minerals. The average activity concentrations of radioactive elements such as 232Th, 238U and 40K were measured by gamma ray spectrometry using a HPGe detector, and found to be 2650±50, 400±30 and 120±30 Bq/kg, respectively, for the bulk sand samples. The activity concentrations in monazite and zircon sands are found to be 305,000±2000 and 2000±150 Bq/kg for the 232Th and 21,500±300 and 3450±250 Bq/kg for the 238U. Electron probe microanalysis results of monazite sands show the average ThO2 and UO3 concentrations to be 10.42 wt.%, and 0.32 wt.%, respectively. The major contributors for the enhanced level of radioactivity are monazite and zircon sands. These heavy mineral sands were derived from the nearby source areas such as Eastern Ghats Group of rocks.
Authors:D. Chowdhury, S. Saha, Sujit Pal and P.K. Mathur
The rare earth elements (REE), Pr, Sm, Eu, Gd, Ho, Er and Tm have been determined by charged particle activation analysis using 40 MeV a-particles through radiochemical approach. The radiochemical separation of REE as a group has been carried out from the bulk matrix. It has been shown from the theoretical computation that the products obtained from (a,xn) reactions (x = 1, 2, 3) are more suitable compared to those from (a,pyn) reactions (y = 0, 1, 2) due to the former having higher cross section (of the order of thousand millibarns).