Biennial Report 2005-2007 - Saha Institute of Nuclear Physics

52 Biennial Report 2005-07Kr II: 5p 4 P 3/2 (6.85±0.13), 5p 4 D 7/2 (7.01±0.14)MB Das, S Karmakar†NAP2.4 Applied Nuclear Science2.4.1 Impact Phenomena, Irradiation Effects and Positron Annihilation Studies2.4.1.1 Theoretical assay: Application of positron annihilation study towards molecularimaging modalityA detailed review work was organized as an application of the positron annihilation study, towardsPositron Emission Tomography (PET) which is an imaging modality for medical diagnoses thatcan determine biochemical and physiological processes in vivo in a quantitative way by, using radiopharmaceuticals labeled with positron emitting radio nuclides. This concise report was broughtabout (publishable) that describes the various aspects of its basic physics, critical design and instrumentationalong with the modalities of the application of radiotracers and the radiologicalprotections involved in the processes. It further suggests critically, the future scope of improvementsin terms of better sensitivity, local and kinetic resolution, specific tracer targeting, includingchemical speciation and better spatial resolution of the PET image. Some theoretical inputs andcritical judgment is added. Some of the emphasis was on the following aspects, such as : new experimentsrelating to PET, Radiotracers in use, Imaging modalities, Scintillation detectors (specialdesign), Time of flight (TOF) measurements, Radiological protection etc.Bichitra Ganguly, Nagendra Nath Mondal, Maitrayee NandyNAP2.4.1.2 Experimental work: Temperature Dependent Positron Annihilation Study ofCinnamic Acid, a view of its structural aspectsCinnamic acid is an essential constituent of cinnamon extract (oil), well known for its medicinal values.Most significantly, it is an important pathway for useful pharmaceuticals. Its main structuralfeature, which is basically phenyl acrylic acid: is strong hydrogen bonding between the carboxylicgroups. The dimers are also interconnected by CH...O intermolecular hydrogen bonds, with C-Hunit mostly originating from aromatic ring. These bonds keep the dimers and higher oligomerstogether and thus the compound exists in a crystalline form. Its crystal structure depict stackedarrangement of parallel layers of molecules with intermittent inter/intra molecular hydrogen bonding(viz, CH...O and OH...O) within a layer. A temperature (higher than the ambient temperature)dependent positron annihilation study (both the life time and Doppler broadening of annihilationresults) on the above molecular configuration was performed. Results show intriguing variationsascribable to the subtle changes in molecular configurations. The supportive evidences are soughtthrough independent investigations using differential scanning calorimetric (DSC) results. Further,TEM investigation of the dispersed cinnamic acid powder in n- hexane to study the stacked structurewas also done with repetitive reproducibility of the results.Bichitra Ganguly, Nagendra Nath Mondal, SK Bandopadhyay†, Pintu Sen†NAP