Department of Physics, Panjab University, Chandigarh, India

TPSC seminar

Time and date: 7 December 2010 (Tuesday), 4:00 PM
Venue: Seminar Hall

Title: The transient field measurements of pico-second lifetime nuclear states at ANU

Speaker: Dr. Sanjay Kumar Chamoli, Department of Physics & Astrophysics, University of Delhi, Delhi

Abstract: Nuclear g factors depend on the single particle orbitals occupied by the protons and neutrons in the nucleus. So any nuclear state formed by the occupied orbitals can be uniquely probed by measuring the g factor of that state. Their sensitivity to the small admixtures in wave function makes them a much superior tool to test the nuclear models compared to the electromagnetic transition rates which require the knowledge of both initial and final state wave functions for interpretation. Now depending upon the lifetime and the spin involved several techniques of g factor measurement have been developed and tested successfully. One of such techniques, the transient magnetic field (TF) technique specifically applies to measure the g factor of pico-second lifetime states. Using this technique, a number of g factors of the first few excited states in stable nuclei have been measured over the last four decade. The growing availability of good intensity radioactive ion beams at various research facilities has motivated people to look for a possibility of applying the TF technique to the exotic nuclei also. However, the success of TF measurements with radioactive ion beams heavily rely on the availability of a suitable calibrator (stable nucleus) with precisely known (better than 10%) g factor. The available g factor data of stable nuclei in this respect is not very encouraging and errors as high as 50% has been reported in some cases. So a revisit of the stable beam measurements with improved setup, detection methods and analysis techniques is highly required. To carry out such TF measurement with stable beams, a highly efficient dedicated setup HYPERION has been made at the Australian National University (ANU), Canberra. With this setup a number of precise (error ~ 10%) measurements have already been reported.