Production and Separation of Carrier free Radionuclides by Heavy Ion Activation
For the first time, systematic studies on the heavy ion induced production of carrier free radionuclides of lanthanide series elements, third transition series elements, s-and p-block elements and their separation from the bulk target.
In order to produce carrier-free radionuclides, generally proton or alpha beams are used as projectiles. We observed that the radiochemical purity of light charged particle induced rare earth radionuclides are extremely poor. This is due to the fact that light charged particle induced reactions produce adjacent radionuclide having pronounced similar chemical properties between the target and product and thus the separation become very difficult specially when one has to separate carrier-free lanthanide radionuclide (i.e. in ultra trace scale) from target matrix (present in macro scale). To get rid off this monotonous similar property, heavy ion activation was done where the product radionuclides are well separated by their atomic number from the target element which helps to overcome the difficulty of separation arising from the intrinsic similar property of the lanthanide series elements.
By applying heavy ion activation techniques, we were able to produce and separate high purity carrier free radionuclides, like, 135Ce, 145-147Eu, 147,149Gd, 150-153Tb, 150-153Dy, 163,165-167Tm, 163,165-167Yb, etc. These radionuclides are proton rich and advantageous due to their shorter and convenient half lives than those are currently used in biomedical fields. The proposed radionuclides can serve as better alternative than those currently used in biomedical fields.
Similar to rare earth radionuclide we have also produced and separated carrier free radionuclides in high purity in other parts of the periodic table, like 24Na, 28Mg 48V, 48,49Cr, 181Re, 176,177W, 176,177Ta, 187,188Pt and 187,188Ir, etc.
Another significant work is the development of alternative methods for the production as well as radiochemical separation of 67Ga, 111In and 199Tl radionuclides which have elegant importance in nuclear medicine. Natural cobalt, a mononuclidic element, was used as target and heavy ions like 11B/12C as projectiles. 67Ga was produced with high radiochemical as well as and radioisotopical purity. 7Li irradiation of natural silver and gold target produces 111In and 199Tl respectively.
Introduction of Tracer Packet Technique
Recently we have introduced and established the
conception of “Tracer Packet” which can be defined as a group of carrier-free radioactive
isotopes of a few elements which have been produced together with an objective
to study some particular physical, chemical or biological systems. The idea of “Tracer packet” is complementary to “Multitracer”
which was discovered and established at RIKEN in
Application of Tracer Packet Technique to Bio-environmental Remedeation
Of late, we are engaged with environmental
studies with “tracer
packet technique”. This technique is applied in the study of
the mechanism of bio-accumulation of heavy and toxic metals in algae which are
the primary producer in aquatic ecosystem. Different groups of algae were
tested at different experimental conditions to select an
useful group for such study. It has been found that Spirulina from cyanophyceae can accumulate heavy and toxic metals, such
as, Hg, Pb, Bi and