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Lifetime measurement

I have worked on the following lifetime measurement techiques:
1) beta-x-ray-electron triple coincidence technique: This technique was based on the beta-gamma-gamma technique developed at Brookhaven National Laboratory. This technique, developed at Oak Ridge National Laboratory, involves measurement of lifetime of a level which decays only via a electric monopole transition. The x-ray emitted during the internal conversion is used along with the beta feeding of the level to get the lifetime measurement information. The electron emitted during the internal conversion is used as the gate to pick out the correct x-ray.
2) x-ray-x-ray-electron triple concidence technique: Theis technique was also developed at ORNL for the case where the beta decay feeding a level is replaced by electron capture feeding.
3) Doppler Shift Attenuation Method: Here the energy level of interest is fed from upper levels and decays, while still in motion in a target backed by a heavy metal. During the slowing down of the nucleus, the decay of the level results in a distribution of the Doppler shifted gamma rays. A distribution simulated on the basis of the energy loss information inside the target and the backing is compared with the experimentally obtained spectra and this gives the lifetime information of the level.
4) Recoil distance method: In the case defined in 3) above the if the lifetime is longer compared to the time taken for the nuclei to slow down inside the target, the target and the backing are separated by a micron level distance. The nuclei then decay in-flight or after stopping in the absorber. The intensity of the stopped and the shifted peak depends on the distance between the absorber and the target. Based on the change in the intensity as a fuction of the absorber-target distance the lifetime can be determined.
5)Beam Pulsing: When the lifetimes are in the nanosecond region a pulsed beam is incident on the target and the intensity of the decay of the level is studied as a fuction of time lapse from the arrival of the beam pulse. This decay rate is used to obtain the lifetime information.

Super deformation

The nucleus when deformed to the size of a rugby (i.e. the ratio of the major to minor axis being 2:1) is a rigid rotor. With its moment of inertia being constant as its rotation slows down it gives out gamma-rays which are differ by nearly same energy. These nuclei have however not revealed very much the secret of how they connect to the bands with normal deformation. This link has been detected in few cases. I have worked on the project to see if this decay is via pair production or via high energy electric monopole transitions.

Teaching

I have been teaching Theory of Relativity at the course on Conciousness Studies conducted jointly by BITS, Pilani BITS Pilani and Bhaktivedanta Institute, Mumbai.