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Cross-section for transfer reactions 90Zr(16O, X) have been measured at an incident energy of 90 MeV. The angular distribution of the elastic scattering 90Zr(16O,16O)90Zr, the inelastic scattering to excited states of 90Zr, the one-nucleon transfer reactions 90Zr(16O,15N)91Nb (g.s., 0.104 and 3.37 MeV states), 90Zr(16O,15O)91Zr (g.s. and 2.17 MeV state) 90Zr(16O,17O)91Zr (g.s.) and the two-nucleon transfer reactions 90Zr(16O,14C)92Mo (ground and 1st excited states) are analyzed in the coupled-reaction-channel (CRC) formalism. Starting with a double-folded real potential, the elastic-scattering angular distribution is calculated using the CRC code FRESCO. The absorptive potential is then generated through the coupling of various inelastic and transfer processes that occur at the nuclear surface. Addition of a short-range imaginary potential in the coupling scheme, whose purpose was to take into account the effect due to loss of flux in fusion channel, reproduces the measured elastic-scattering angular distribution. A good description of all the quasi-elastic data has been achieved and the absolute magnitudes are reproduced without any arbitrary normalization. The relative importance of the one-step cluster transfer of two protons vs. the two-step successive transfer has been studied.

We present a method to determine precisely the absolute momentum of the external proton beam from the Julich Cooler Synchrotron COSY near 1930 MeV /c . In the pp → d π + reaction at 1930.477 MeV /c incident beam momentum, the forward going pions ( θ c.m. =0° ) and the backward going deuterons ( θ c.m. =180° ) have the same laboratory momentum. Such coincident pion–deuteron events are detected in the focal plane of the magnetic spectrometer BIG KARL located at θ lab =0° . Using the nearly linear dependence of the difference between the measured pion and deuteron momenta as a function of the proton beam momentum, the absolute momentum of the external proton beam from COSY near 1930 MeV /c was determined with a precision of 5.2×10 −5 .

A stack of annular detectors made of high-purity germanium was developed. The detectors are position sensitive with radial structures. The first one (“Quirl”) is double-sided position sensitive defining 40 000 pixels, the following three (E1, E2 and E3) have 32 wedges each. The Quirl acts as tracker while the other three act as calorimeter. The stack was successfully operated in meson production reactions close to threshold.

Multi-nucleon transfer reactions 115In(12C,X with X = 14 C , 13 C , 11 C , 12 B , 11 B, 10 B , 10 Be , 9 Be , 7 Be , 7 Li , 6 Li and 6 He have been studied at an incident carbon ion energy of 84 MeV. Absolute cross sections have been measured. Energy spectra are examined in terms of a constrained phase space approach where the observed optimum Q-value forms the constraint.

vhoice Cross sections for multinucleon transfer reactions are measured at several angles in the reaction 88 Sr( 12 C,X) - X ranging from 9 Be to 14 C at an incident carbon-ion energy of 87.5 MeV. In case of single-nucleon transfer reactions, the measured angular distributions of cross sections in transition to the ground and low-lying states in the 87,89 Sr and 89 Y nuclei are described well in terms of finite-range DWBA calculations. The transfer probability obtained from the experiments to well-defined shell-model orbits forms the single-particle unit for evaluation of the mechanism in multinucleon transfer reactions. The analysis reveals a small enhancement of the transfer probability corresponding to a proton-pair stripping. The mechanism of one-step “direct” transfer of a cluster is predominant in deuteron and 3 He transfer reactions. However, the transfer of a neutron pair seems to proceed through a sequential transfer of two neutrons.

The proton-stripping reaction 115 In( 12 C, 11 B) 116 Sn has been studied using 84 MeV 12 C beams. Two groups of states centred at 4.2 and 5.5 MeV excitation in 116 Sn probably have configurations involving particle-hole states of ( 1 g −1 9 2 , 1 g 7 2 ) and ( 1 g − 9 2 , 1 h 11 2 ) origin. The identification is based on the published light-ion-induced proton-transfer studies as well as the shell- model calculations. The angular distributions and the excitation functions for the two groups have been measured and analysed in terms of the finite-range DWBA. The optical potentials in the entrance channel have been determined by fitting the measured elastic angular distribution data. The consistency of the normalisation constant determined indicates that the dissipation mechanism, at least, for the one-nucleon transfer stage proceeds predominantly through the direct reaction mechanism.

The analogues of the low-lying levels in71Ge have been observed as resonances in the compound nucleus71As through proton elastic scattering on70Ge in the energy rangeE p=3.5 to 5.3 MeV. The excitation functions cover the analogue resonances corresponding to states upto 2.3 MeV excitation in71Ge. The sub-structures in the 5.06 MeV resonance, first observed by Temmer and co-workers have been confirmed in the present experiment. The present investigation reveals similar sub-structures in the 4.13 MeV resonance lending further support to the existence of intermediate structure near an isobaric analogue resonance. The resonance parameters and the spectroscopic factors (for the corresponding parent states) have been extracted. The results are compared with the information available from the70Ge(d, p)71Ge reaction.

A compact, low emittance duo plasmatron ion source and an extraction system have been designed and built, primarily as an injector to a 2 MV Tandem Van de Graaff accelerator being built at Bhabha Atomic Research Centre, Bombay. With this system we have extracted 5 mA N + , 3 mA of Ar + beams and 200 A of N − beam. The emittance and brightness for the source are measured and are 3.66×10 −2 mm-mrad and 10 10 mA/cm 2 - rad 2 respectively.

The low-lying states of 73Ge have been excited as isobaric analogue states in 73As by the proton bombardment of 72Ge. The decay of these states to the first excited state (0+) in 72Ge at 690 keV has been observed, and the accompanying conversion electrons have been detected using an orange spectrometer. The excitation function covers isobaric analogue states of 73Ge up to an excitation of 1.32 MeV. From the measurement of the total inelastic cross section the partial widths for the states have been calculated. On the basis of these results, the levels at 67 and 673 keV in 73Ge are interpreted to be single-particle neutron states built on the second 0+ state in 72Ge.

States have been observed in the compound nucleus 73 As through the study of elastic scattering of protons on 72 Ge which are the isobaric analogues of the low-lying levels of 73 Ge. The excitation functions cover the first five levels. Two of these being l = 4 transitions are not observed in our study because of the low barrier transmission. l -values have been assigned to the states from the analysis of the differential cross sections. The results are compared with available evidence from other experiments on 73 Ge.

Low-energy gamma rays following compound nuclear reactions ( 3 He, 3n) on Te, Sn and Cd isotopes have been studied with a Ge(Li) counter at incident energies up to 19.3 MeV. Based on the systematics, the levels at 602 keV and 1160 keV in 118 Te have been assigned to be the 2 + and 4 + levels. Similarly the level at 607 keV in 116 Te has been assigned to be 2 + . Gamma rays corresponding to the transitions connecting lower-spin states at higher excitations were not observed. The success in observing higher-spin states, therefore, depends not merely on the higher angular momentum brought in by the incident particles but rather on the (2 J + 1) weight factor for the higher-spin states, which is characteristic of any compound nuclear reaction.

Es wurden die Reaktionen 30Si(d, p)31Si bei Ed = 10 MeV und 30Si(3He, d)31P bei E3He = 15 MeV mit einem Breitbandmagnetspektrographen untersucht. Für 31Si wurden Winkelverteilungen für 20 Niveaus von 5° bis 120° gemessen und mit einer DWBA Analyse wurden l-Werte und spektroskopische Faktoren bestimmt. Auf Grund der Targetzusammensetzung wurden zugleich mit dem 31Si 23 Niveaus im 29Si gemessen, deren spektroskopische Faktoren mit früheren Messungen 1 übereinstimmen. Die l = 2 Winkelverteilungen sind strukturiert oder flach je nach dem dem Spin 3/2+ oder 5/2+ des Endzustandes, so daß sich durch Vergleich auch die Spins der Niveaus im 31Si bestimmen ließen. Im 31P wurden die l-Werte und relativen spektroskopischen Faktoren aus 4 Spektren bei 4 ausgewählten Winkeln bestimmt. Eine Interpretation der Niveaustruktur und der spektroskopischen Faktoren von 31Si und 31P nach den Schalenmodellrechnungen von GLAUDEMANS et al. 2 schlägt fehl, vor allem da in den Rechnungen die d5/2 Schale als abgeschlossen betrachtet wird. Die versuchsweise Anwendung des NILssoN-Models führt auf kleine Deformationen | η | < 2, ohne die Niveauleiter indessen exakt erklären zu können.

Angular distributions for α-particles and deuterons from the reactions 66Zn(3He, d)67Ga and 66Zn(3He, α)65Zn have been measured at an incident 3He energy of 18 MeV, using a broad-range magnetic spectrograph. DWBA analysis gives information about the 66Zn ground state configuration as well as the neutron hole states in 65Zn and the single-particle proton states in 67Ga. p]Analogue states in 65Zn corresponding to low-lying levels in 65Cu and in 67Ga corresponding to low-lying levels in 67Zn have been identified.

The reactions 64 Zn( 3 He, d) 65 Ga and 64 Zn( 3 He, α) 63 Zn have been studied at incident 3 He energy of 18 MeV using a broad range magnetic spectrograph and an E -d E telescope. Angular distributions have been obtained and are analysed by the DWBA theory. The results give information about the 64 Zn ground state configuration as well as the neutron hole states in 63 Zn and the single proton states in 65 Ga, respectively.