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Y. K. Agarwal

Bio: Y. K. Agarwal is an academic researcher from Tata Institute of Fundamental Research. The author has contributed to research in topics: Electron spectroscopy & Internal conversion. The author has an hindex of 5, co-authored 14 publications receiving 103 citations.

Papers
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Journal ArticleDOI
TL;DR: In this paper, an analysis of 32 S + 64 Ni fusion excitation data has been performed to derive an empirical barrier distribution in order to investigate the relationship between the simplified coupled-channel model and the neutron-flow model.

56 citations

Journal ArticleDOI
01 Oct 1974-Pramana
TL;DR: In this article, the level scheme of 75Se has been studied through the 75As (p, n) reaction at proton energies from 1.5 to 5.0 MeV.
Abstract: The level scheme of75Se has been studied through the75As (p, n) reaction at proton energies from 1.5 to 5.0 MeV.γ-ray and internal conversion electron measurements were made using NaI (T1) and Ge(Li) detectors and a six-gap electron spectrometer. A proportional counter and a thin window NaI(T1) detector were used to detectγ-rays with energies less than 30 keV. The level scheme has been established by observing the thresholds of variousγ-rays and byγ-γ and e−-γ coincidence measurements. New levels at 133.0, 293.2, 790.0, 953.0, 1020.8, 1184.3, 1198.5 and 1258.2 keV not observed in earlier (p, n) studies have been established. Conversion coefficients of most of the low-lying transitions have been determined. Angular distributions of some of theγ-rays were also measured and compared with the statistical model calculations. DefiniteJ π assignments have been made to most of the low-lying levels. Life-times of the 112.1, 133.0, 286.7 and 293.2 keV levels have been measured to be 0.69±0.12, 5.3±0.6, 1.35±0.15 and 31±2 nsec respectively. The reduced transition probabilities for various low-lying transitions have been determined and compared with recent calculations. The 1/2− and 9/2+ levels hitherto unknown in this nucleus has been identified. The structure of the low-lying levels is discussed in terms of the existing models.

11 citations

Journal ArticleDOI
01 Sep 1991-Pramana
TL;DR: A plunger set-up has been designed and constructed to measure picosecond nuclear half-lives using recoil distance method (RDM) as discussed by the authors, which has been used to measure the half-life of nuclear states in 35Cl,37,38Ar and 40K.
Abstract: A plunger set-up has been designed and constructed to measure picosecond nuclear half-lives using recoil distance method (RDM). The system has been used to measure the half-lives of nuclear states in35Cl,37,38Ar and40K. The shortest half-life measured with the system isT 1/2=0.36(14) ps for the 4366 keV (8+) state and the longest half-life isT 1/2=1.10(7) ns for the 2543 keV (7+) state in40K.

11 citations

Journal ArticleDOI
TL;DR: It is seen that the Tl nuclei are nonspherical at the excitation energies and spins relevant for the present work and an attempt has been made to extract information on shape fluctuations directly from the {gamma} spectra.
Abstract: The present paper describes the measurement of high energy gamma rays ({approximately}5{endash}22 MeV) in the reaction {sup 16}O+{sup 181}Ta. Singles measurements were performed at {ital E}({sup 16}O)=84, 89, and 107 MeV and the multiplicity gated measurements along with the angular distributions were made at {ital E}({sup 16}O)=94 MeV. It is seen that the Tl nuclei are nonspherical at the excitation energies and spins relevant for the present work. The angular distribution data can be explained only by incorporating large orientation fluctuations. An attempt has been made to extract information on shape fluctuations directly from the {gamma} spectra. Under the restriction of using a common {open_quote}{open_quote}intrinsic{close_quote}{close_quote} strength function characterized by {ital E}{sub 0} and {Gamma}{sub 0} for the multiplicity gated data sets, a small increase of the effective mean deformation and a drive towards triaxiality ({gamma}{approximately} 30{degree}) with angular momentum is brought out. If this restriction is relaxed, however, the data can be understood also with a smaller value of {gamma}. The singles data can be understood within the same framework with a higher value of {Gamma}{sub 0}. {copyright} {ital 1996 The American Physical Society.}

7 citations

Journal ArticleDOI
01 Jul 1990-Pramana
TL;DR: An array of seven hexagonal NaI(Tl) detectors has been set up for measuringγ-ray spectra in the energy region 5 MeV ≤E ≥ 40 MeV with good accuracy as discussed by the authors.
Abstract: An array of seven hexagonal NaI(Tl) detectors has been set up for measuringγ-ray spectra in the energy region 5 MeV ≤E γ ≤ 40 MeV with good accuracy. This is in contrast to earlier set ups which mostly used one large sized (about 10 inchesφ × 15 inches long)NaI(Tl) detector. This set up has been made for the study ofγ decay of GDR based on high spin states and ultra-dipole radiations. The array has been provided with the following features: a) TOF discrimination against neutrons, b) pile up detection and elimination, c) active and passive shielding to cut down background and d) an array of trigger counters for multiplicity dependence measurements. The well known program EGS4 has been used to determine the response of the array forγ-rays in the energy region 5–40 MeV and several test measurements have been carried out to confirm the validity of the calculated response functions. Some typicalγ-ray spectra fromα and16O induced reactions measured at VECC, Calcutta and Pelletron accelerator at TIFR are also shown.

5 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, a quantitative understanding of the entrance-channel effects induced by target and projectile structure has emerged, based on recent high-precision measurements of fusion excitation functions.
Abstract: ▪ Abstract The experimental extraction of detailed barrier distributions has brought a significant advance in the study of the fusion of heavy nuclei, and indeed in the entire heavy-ion reaction process. A quantitative understanding of the entrance-channel effects induced by target and projectile structure has emerged, based on recent high-precision measurements of fusion excitation functions. These distributions show clearly whether the experimental data are good enough to give the information required. They are also the functions best suited to the theoretical interpretation of the reaction dynamics—often presenting an unambiguous “fingerprint” of the target and projectile structure. We are now at the stage where we can start to exploit the insights gained in order to understand properties of the compound nucleus created: its spin distribution and evaporation residues, perhaps its possible shapes, and, in the case of heavy systems, its subsequent fission.

444 citations

Journal ArticleDOI
TL;DR: In this paper, the role of nucleon transfer, asymmetry effects, higher-order couplings, and shape phase transitions in heavy-ion fusion reactions below the Coulomb barrier is discussed.
Abstract: Recent theoretical advances in the study of heavy-ion fusion reactions below the Coulomb barrier are reviewed. Particular emphasis is given to new ways of analyzing data (such as studying barrier distributions), new approaches to channel coupling (such as the path-integral and Green's function formalisms), and alternative methods to describe nuclear structure effects (such as those using the interacting boson model). The roles of nucleon transfer, asymmetry effects, higher-order couplings, and shape phase transitions are elucidated. The current status of the fusion of unstable nuclei and very massive systems are briefly discussed.

325 citations

Journal ArticleDOI
P.M. Endt1
TL;DR: In this paper, the experimentally determined properties of A = 21−44 nuclei are compiled and evaluated with special emphasis on nuclear spectroscopy, and a supplement to the most recent complete complete A =21−44 review (90En08) is presented.

225 citations

01 Jan 1989
TL;DR: In this article, the excitation energy of the first 3-state of even-even nuclides is tabulated and adopted values of the reduced electric-octupole transition probability, B(E3;O: + 3;), from the ground state to this state, as determined from Coulomb excitation, lifetime measurements, inelastic electron scattering, deformation parameters /3s obtained from angular distributions of inelastically scattered nucleons and light ions, and other miscellaneous procedures are listed in separate tables.
Abstract: Adopted values for the excitation energy, &(3;), of the first 3- state of even-even nuclides are tabulated. Values of the reduced electric-octupole transition probability, B(E3;O: + 3;), from the ground state to this state, as determined from Coulomb excitation, lifetime measurements, inelastic electron scattering, deformation parameters /3s obtained from angular distributions of inelastically scattered nucleons and light ions, and other miscellaneous procedures are listed in separate tables. Adopted values for B(E3;O: + 3;) are presented in the final table, together with the E3 transition strengths, in Weisskopf units, and the product EA3;) X B(E3;O: --* 3;), expressed as a percentage of the energyweighted E3 sum-rule strength. An evaluation is made of the reliability of B(E3;O: + 31) values deduced from deformation parameters &. The literature has been covered to March 1988.

167 citations

Journal ArticleDOI
TL;DR: In this paper, precise fusion and quasi-elastic scattering excitation functions have been measured for the systems 40 Ca + 90,96 Zr at energies spanning the Coulomb barrier.

156 citations