[en] Angular distributions of vector analyzing power and cross section for the reactions ⁴⁰Ar(d,p)⁴¹Ar and ⁴⁰Ar(d,t)³⁹Ar have been measured at an incident deuteron energy of 14.83 MeV. The bound-state data in the (d,p) reaction and the (d,t) data are compared to DWBA calculations. The data for the neutron-unbound states are analyzed in the framework of the DWBA using (i) a form factor for weakly bound neutron and (ii) a resonance form factor, following the approach of Vincent and Fortune. The j-dependence of the (d,p) vector analyzing power permits definite spin-parity assignments to be made for 19 neutron-bound and 4 neutron unbound states in ⁴¹Ar with excitation energy up to 6.57 MeV. Tentative Jsup(π) assignments have been made for 3 states. The l-value for the 5.62 MeV states has been determined. Data for the observed unbound states are found to be equally well reproduced by the type (i) calculations as by the type (ii) calculations. The (d,t) vector cnalyzing power data show definite J-dependence although not as strongly as in the (d,p) reaction. For relatively weakly excited states a pre-knowledge of the l-value of the transition is desirable for an unambiguous spin assignment. In general, the J-dependence in the (d,t) vector analyzing power can be utilized for definitive Jsup(π) assignments. On this basis, Jsub(π) values have been assigned for seven states in ³⁹Ar with excitation energies up to 4.47MeV excitation. Possible spin values for three other states are suggested. Spectroscopic factors fo the states in ⁴¹Ar and ³⁹Ar have been extracted and are in fair agreement with those obtained by other workers. (Auth.)

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[en] A sputter ion source, Hiconex Model 833, is mounted in the terminal of the Notre-Dame +- 4MV electrostatic accelerator. The terminal contains a gridded einzel lens, an accelerating gap for external beam focus, and a 9⁰ electrostatic deflector which prevents neutral caesium atoms from reaching the accelerating tube. Source parameters are observed through a 16 channel modulated light beam telemetry system. The existing terminal voltage stabilizing system which controls belt charge and tank liner voltage was modified for improved response to the generating voltmeter. A new generating voltmeter circuit which has no inherent frequency limitation has been developed and is functionning. Magnetic and electrostatic analysis of the accelerated negative ion beam provide mass resolution of 1.4% (measured) and energy resolution of 0.1% (calculated). Electrostatic steering and focusing elements transport the analyzed beam through 34 meters and a 123⁰ deflection for injection into an FN Tandem. In early testing at 2MeV, an analyzed beam of 4 μA of ¹²C was obtained. We have also measured 50 nA of ¹¹B, completely resolved from the ¹⁰B component and also from a large ¹²C contaminant beam

[en] The value of the electron capture branching ratio of ⁷Be to the 478 keV state in ⁷Li has been measured using sources of determinable intensity fabricated by capturing in silicon surface barrier detectors ⁷Be recoils from the ¹⁰B(p,α) ⁷Be reaction at E/sub p/ = 1.5 MeV and 4.5 MeV. Results from independent measurements utilizing detectors implanted in a scattering chamber and in the focal plane of a magnetic spectrograph are in good agreement. An absolute determination of the rate at which the 478 keV gamma rays were emitted from each source yielded a weighted average value of 10.6 +- 0.5 % for the branching ratio. This result is in agreement with the previously accepted value of 10.37 +- 0.12 % and does not support the recent suggestion that the branching ratio is appreciably larger

[en] Precise level energies in ³⁸K have been measured up to the region of 6 MeV in excitation with our 100-cm broad-range magnetic spectrograph and the ⁴⁰Ca(d,α) reaction. With a Ge(Li) detector, γ-ray energies were measured in the ⁴⁰Ca(d,αγ) and ³⁶Ar(³He,pγ) reactions. Some 79 states have been identified in this region of excitation, approximately 30 of which have not previously been reported. Uncertainties in excitation energies are 1 to 3.5 keV. Branching ratios for levels up to 5.2 MeV were determined, and particle-γ angular correlations were measured with the ³⁶Ar(³He,pγ) reaction. The mean lives of some levels in ³⁸K excited in the ⁴⁰Ca(d,αγ) reaction at E/subd/ = 7.84 MeV have been determined using the Doppler-shift attenuation method. The following mean lifetimes were deduced (excitation energy in keV, lifetime fs): 3431, < 170; 3615, 700/sub -//sub 3//sub 1//sub 0/⁺⁸⁵⁰; 3688, 95 plus-or-minus 55; 3688, 400/sub -//sub 1//sub 2//sub 0/⁺¹⁶⁰; 3702, > 1100; and 4333, 350/sub -//sub 2//sub 5//sub 0/⁺⁷⁰⁰. The angular correlations, with the lifetimes were deduced (excitation energy in keV, lifetime infs): 3431-, 3615-, and 3688-keV levels, respectively: J/sup pi/ = (2), (3^- or 5^-), (3), where parentheses indicate assignments dependent upon unproven assignments to other levels from the literature. The observed decays further imply J = (1,2) for both the 3857- and 4214-keV levels. Clarifications of several ambiguous and erroneous level identifications in the literature are offered