S CHANDA¹ ,   SARMISHTHA BHATTACHARYYA², TUMPA BHATTACHARJEE², S S GHUGRE³, SWAPAN KUMAR BASU², S MURALITHAR⁴, R P SINGH⁴, B MUKHERJEE⁴, R K BHOWMIK⁴ and S N RAY⁵

 ¹ Fakir Chand College, Diamond Harbour, West Bengal

² Variable Energy Energy Cyclotron Centre, Kolkata 700 064, India

³  Inter University Consortium for DAE Facilities, Kolkata 700 091, India

⁴  Nuclear Science Centre, New Delhi 110 067, India

⁵  Physics Department, Viswabharati University, Santiniketan, West Bengal

Abstract.

The high spin states in N=80 ¹³⁹ Pr have been investigated by in-beam g-spectroscopic techniques following the reaction ¹³⁰Te (¹⁴N, 5n) reaction at E = 75 MeV, using a gamma detector array, consisting of seven 23% compton-suppressed high purity germanium detectors and a multiplicity ball of fourteen bismuth germanate elements. Based on g--g coincidence data, the level scheme of ¹³⁹ Pr has been considerably extended up to 7.2 MeV excitation. Tentative spin-parity assignments are done for the newly proposed levels on the basis of theDCO ratios corresponding to strong gates and the available information from the earlier light ion experiments.

Keywords:  High spin states; nuclear structure; gamma-ray spectroscopy;¹³⁹ Pr energy levels.

Pacs Nos.  21.10.-k; 23.20.-g; 27.60.+j; 29.30.Kv