R. P. Singh

Characteristics of a Compton suppressed Clover detector up to 5 MeV

The Clover detectors in their addback mode are excellent tools for detecting high-energy gamma rays ðX2 MeVÞ: The characteristics ofthese detectors, at energies above 2 MeV ; are usually determined from simulation data or from extrapolation ofthe empirical data. This is the first time that the characteristics ofa Compton suppressed Clover germanium detector have been studied up to 5 MeV using a radioactive 66 Ga ðT1=2 ¼ 9:41 hÞ source. r 2002 Elsevier

Band structure of 79Br

Abstract High-spin states of 79Br have been studied in the reaction 76 Ge( 7 Li , 4nγ) at 32 MeV. A gamma-detector array with twelve Compton-suppressed HPGe detectors was used. The positive-parity yrast states, interpreted as a rotationally aligned g 9 2 proton band, and the negative-parity ground state band have been extended to spins of ( 33 2 + ) and ( 25 2 − ), respectively. Lifetime measurements indicate that both bands have a similar quadrupole deformation of β2 ∼ 0.2. The positive-parity α = −1 2 band has been identified. Several new inter-band transitions are observed. A cranked-shell model analysis shows that the νg 9 2 alignments occur in the positive-parity and the negative-parity bands at rotational frequencies of ℏω ∼ 0.6 and 0.4 MeV, respectively. The level energies and the electromagnetic properties of the g 9 2 band can be well reproduced by a particle-rotor model calculation with an axially symmetric core.

Rotational bands in the doubly odd 138Pm

Abstract The band structures of the doubly- odd 138Pm nucleus have been investigated using the 115In(28Si, 2p3n)138Pm reaction at a beam energy of 145 MeV. The three previously known rotational bands viz., (i) the yrast one based on the πh 11 2 ⊗ νh 11 2 configuration, (ii) a ΔI = 2 band with πh 11 2 ⊗ ν[400] 1 2 + configuration at lower frequency but with a change in the neutron configuration to ν[660] 1 2 + at higher frequency, and (iii) one consisting of stretched E2 cascades at lower frequency but of dipole transitions after backbend and with suggested configuration of π[413] 5 2 + ⊗ νh 11 2 have been modified and extended to higher spins. Two new bands have been identified. Of these, one consists of only quadrupole transitions, similar to that observed in band (iii), mentioned above, while the other consists of dipole transitions. The observed level properties have been compared to theoretical calculations performed within the Particle Rotor Model (PRM) with axial core and cranked shell model. The experimental branching ratios and B (M1) , B (E2) ratios of the transitions in the yrast band are well reproduced by PRM, assuming an axial prolate core.

Structure of positive-parity yrast band in 80 Br

Abstract The states of the positive-parity yrast band in 80 Br have been investigated using the 76 Ge( 7 Li, 3n γ ) reaction at a beam energy of 32 MeV. The band has been extended up to 4450 keV with a spin of (14 + ). Unambiguous spin assignments are made for states up to 2944.0 keV and γ -ray multipole mixing ratios are determined for several ΔJ=1 transitions. Lifetimes studies for the 10 + , 11 + and 12 + states provide an estimate of the quadrupole deformation in this band. Cranking model analysis of the experimental data reveals a signature inversion at a spin of 12 ℏ and a probable neutron alignment at ℏω≈0.7 MeV. The results are discussed within the framework of the systematics of similar bands in the lighter Br isotopes and the cranked-shell model. In addition, a new positive-parity and two negative-parity sequences have been identified.

Structure of 96 Mo at high spins

Abstract High-spin states of 96 Mo ( Z=42 , N=54 ) nucleus have been investigated through the 82 Se( 18 O , 4n ) reaction at E b =60 MeV. The excited states have been extended upto 10 MeV and the levels with J π =20 + spins have been observed in the present experiment while the earlier information for the same was available only upto 4.8 MeV. A significant modification of the existing level scheme is also being proposed. The properties of the observed levels have been compared with shell-model calculations using OXBASH code. The analysis of the result shows that level structure exhibits mainly single particle character.

A study on adoption of modern agricultural technologies at farm level in Bihar

Among socio-economic, technological and managerial reasons, ineffective transfer of farm technology is important causal factors for poor performance of agriculture. Transfer of technology has been the major obstacle in achieving the targets in past. Present study deals with level of adoption of modern agricultural technology, access and quality of modern technology, outreach of agricultural extension institutions and problems faced by extension officials in transfer of farm technology in Bihar. Study is based on primary data obtained through survey of farm households, agricultural scientists and extension officers in Bihar. Study revealed the coverage of agricultural development programmes limited to few villages, and line departments still dominating technology transfer arena. Institutions like ATMA and KVK were limited to few activities only. Adoption level of artificial insemination is comparatively high due to active participation of co-operatives and private sector, but less than one fourth of farmers could adopt advanced horticulture and modern crop seeds in Bihar. Small size of land holding and fragmented land emerged as main constraint to adoption of modern horticultural technology in Bihar. While analyzing use of modern varieties of principal crops, comparatively high level of adoption on small and medium farms was observed. Dissemination of information about modern agricultural development projects/ schemes is a necessary factor for adoption of modern technology. ATMA and KVK have performed better in dissemination of the information, however, inadequate staff, infrequent supervision and lack of conveyance facility are most important constraints faced in transfer of technology in Bihar.

Energy levels in 141Nd from fusion evaporation study

The nucleus 141Nd has been investigated using two different heavy ion fusion evaporation reactions, namely 130Te(16O, 5n) at Elab = 80–85 MeV and 124Sn(24Mg,α3n) at Elab = 107 MeV, and the de-exciting gamma rays were detected using HPGe(GDA) and Clover detector (INGA) arrays, respectively. More than 30 new gamma transitions have been placed in the proposed level scheme, which has been extended up to 9 MeV excitation energy and spin parity values of 45/2−. Spin parity assignments have been made to most of the newly proposed levels. The structure up to approximately 6 MeV excitation energy and spin 31/2− can be explained using the shell model in a truncated basis. The levels with higher spin/energy cannot be described using even the full 50–82 shell, indicating the influence of neutron excitations across the shell gap in this mass region. One M1 band that has been observed is proposed to have a five quasiparticle configuration.

High-spin structures in 112Sb

Abstract A spectroscopic study of 112Sb has been carried out using the 103Rh(12C,3n) reaction. The low energy excited levels are interpreted in terms of two-quasiparticle configurations arising from the proton and neutron motion in the πg 7 2 , πd 5 2 , νg 7 2 , νd 5 2 and νh 11 2 shell model orbitals. A strongly coupled rotational band, most likely based on a deformed πg 9 2 −1 πg 7 2 2 ⊗ νh 11 2 configuration, is identified at somewhat higher excitation energy. The B( M 1) B( E 2) ratios for some of the transitions in the strongly coupled band indicate mixed nature of the intrinsic configuration.

Rotational band in111Sn

Partial level scheme of the neutron deficient111Sn isotope is established upto an excitation energy of about 9 MeV and Iπ=43/2− from γ-rays following103Rh(12C, p3n) reaction. Clear evidence for the existence of a negative parity rotational band aboveγ=23/2−, most probably based on 3p-2h configuration, is obtained.

High Spin States in the Odd–Odd 150Eu Nucleus

High spin rotational bands in the odd–odd 150Eu nucleus, produced in the 148Nd(7Li,5n) reaction, were investigated by in-beam γ spectroscopy. Seven bands above the 588.8 keV (45 ns) isomeric level were observed. Probable single- and double-octupole-phonon coupling states were identified. Two positive parity bands are interpreted in terms of two quasiparticles (a proton and a neutron) coupled to an axially symmetric rotor core. Otherwise, the rest of the high spin levels are described by multiparticle–hole excitations.