• A Jhingan

Articles written in Pramana – Journal of Physics

• Hybrid recoil mass analyzer at IUAC – First results using gas-filled mode and future plans

Hybrid recoil mass analyzer (HYRA) is a unique, dual-mode spectrometer designed to carry out nuclear reaction and structure studies in heavy and medium-mass nuclei using gas-filled and vacuum modes, respectively and has the potential to address newer domains in nuclear physics accessible using high energy, heavy-ion beams from superconducting LINAC accelerator (being commissioned) and ECR-based high current injector system (planned) at IUAC. The first stage of HYRA is operational and initial experiments have been carried out using gas-filled mode for the detection of heavy evaporation residues and heavy quasielastic recoils in the direction of primary beam. Excellent primary beam rejection and transmission efficiency (comparable with other gas-filled separators) have been achieved using a smaller focal plane detection system. There are plans to couple HYRA to other detector arrays such as Indian national gamma array (INGA) and $4\pi$ spin spectrometer for ER tagged spectroscopic/spin distribution studies and for focal plane decay measurements.

• Neutron detector array at IUAC: Design features and instrumentation developments

The characteristics and performance of the newly commissioned neutron detector array at IUAC are described. The array consists of 100 BC501 liquid scintillators mounted in a semispherical geometry and are kept at a distance of 175 cm from the reaction point. Each detector is a $5''\times 5''$ cylindrical cell coupled to $5''$ diameter photomultiplier tube (PMT). Signal processing is realized using custom-designed home-made integrated electronic modules which perform neutron–gamma discrimination using zero cross timing and time-of-flight (TOF) technique. Compact custom-built high voltage power supply developed using DC–DC converters are used to bias the detector. The neutrons are recorded in coincidence with fission fragments which are detected using multi-wire proportional counters mounted inside a 1m diameter SS target chamber. The detectors and electronics have been tested off-line using radioactive sources and the results are presented.

• Measurement of multinucleon transfer cross-sections in 58Ni,56Fe(12C, 𝑥); 𝑥: 13,11C, 11,10B, 10,9,7Be, 8Be𝑔.s. and 7,6Li at 𝐸(12C) = 60 MeV

Cross-sections for one- and multinucleon transfer reactions, namely, 58Ni(12C, 13C), 58Ni(12C, 11C), 58Ni(12C, 11B), 58Ni(12C, 10B), 58Ni(12C, 10Be), 58Ni(12C, 9Be), 58Ni(12C, 8Be𝑔.s.), 58Ni(12C, 7Be), 58Ni(12C, 7Li) and 58Ni(12C, 6Li) have been measured at an incident energy of 60 MeV. The reaction cross-section for the corresponding transfer channels in the system 12C+56Fe have also been measured under the same kinematical conditions. Angular distribution of the elastic scattering cross-section is measured at 60 MeV. The measured elastic scattering angular distributions for these two systems have been analysed using the optical model search code SFRESCO and the potential parameters are extracted. The multinucleon transfer data are analysed to obtain cross-section dependence on the number of nucleons transferred and on the ground state 𝑄-values. The transfer probabilities for multinucleon stripping are extracted. A detailed comparison in the multiparticle stripping and elastic scattering cross-sections between these two systems are made to understand the mechanism of multinucleon transfer and possible role of two extra protons in 58Ni target nucleus as compared to the 56Fe core.

• Pramana – Journal of Physics

Current Issue
Volume 93 | Issue 5
November 2019

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Posted on July 25, 2019