As our knowledge of the nuclear chart is extended towards the proton drip line, away from the valley of stability, new experiments become increasingly difficult because of the fact that such heavy proton rich nuclei are created with extremely low cross-section (~ 10 mb or less) & with a very high fission background. Spectroscopic studies of these nuclei provide a big challenge for the experimentalists. The nuclei near the doubly magic 208Pb are predicted to exhibit various interesting structural phenomena, one of which is wealth of isomerism. However, little experimental data are available in Z > 82, N ≤ 126 mass regions till date. Recently a few spectroscopic investigations on the proton rich lighter Francium (Z = 87) isotopes (A= 206 to 209) have been made. Lots of nuclear phenomena from core excitation populated single particle states to the existence of shears band in these extreme proton rich heavy nuclei were observed. Structure of such trans lead nuclei can be interpreted in terms of the shell model states, and the high spin states of these nuclei are interpreted as single particle configurations arising from the (1h9/2, 1i13/2, 2f7/2) protons and (3p1/2, 2f5/2, 3p3/2, 1i13/2) neutrons. One of the major interests in the spectroscopic investigation of these nuclei is the role played by the i13/2 state in creating isomeric levels which decay through transitions of higher multipolarity, or are hindered by the close proximity of the levels below. A systematic study of these nuclei will possibly reveal many other interesting structural features.
Although our experiment was aimed at exploring the nuclear structure of 208Fr, the yield of 210Fr (for which almost no published data of nuclear structure exists) at 88 MeV was found to be significant to establish its level scheme. The experiment to produce 208,209,210Fr was carried out at the Inter-University Accelerator Centre (IUAC), New Delhi, INDIA, using the Indian National Gamma Array (INGA) of clover detectors at three different beam energies (100, 94 and 88 MeV). Based on the earlier observation of a couple of low lying transitions connecting the 6+ ground state of 210Fr, and a few strong transitions, the excitation function studies of 210Fr at three different energies are done, and found to be in good agreement with similar studies made from independent offline decay analysis reported earlier. Based on our results, a preliminary level scheme for 210Fr is established for the first time. From our γ γΔT correlation analysis, we could find only significant life time of 41.4 ± 2.1 ns of an isomeric transition. Further refinements of analysis, interpretation of the results based on nuclear structure calculations are currently undertaken.