[en] Differential cross sections for the /sup 2/H(γ,p)n reaction were measured at five laboratory angles, from 32⁰ to 130⁰, for photon energies between 100 and 250 MeV. The LEALE quasi-monochromatic photon beam, obtained at Frascati by positron annihilation on liquid hydrogen target, was used; the photon beam spectrum was measured on-line by a pair spectrometer. Preliminary values of angular distributions and total cross sections at three laboratory photon energies are presented

[en] A sensitive profile and position monitor for low intensity positron (approx.= 10^-₉ A) and photon (approx.= 10₈ ν/s) beams is described. It consists of a multiwire chamber with two sensitive planes and additional electronic circuits. The display of the beam profiles, which appears on a standard oscilloscope, is live and quantitative, the effect of adjustments of the beam transport is immediately and continuously visible. (orig.)

[en] The determination of photonuclear cross sections requires a knowledge of the primary photon spectrum. The intensity and the energy spectrum of the Frascati positron annihilation photon beam have been measured by a Komar et al. type quantameter and a pair spectrometer. The present paper concerns the study and the design of the pair spectrometer. In section 2 the general layout of the facility is reported. In section 3 the main characteristics of the magnet are given. Section 4 is concerned with the optical properties of the spectrometer. The detection system, with the associated electronics, is described in section 5. In section 6 the calculation of the spectrometer response function is reported. In section 7 the experimental photon energy spectrum, at positron energy Esub(+) = 200 MeV, compared with the calculated one, is given. (orig.)

[en] We have derived an expression for the cross section for the γd→pn reaction at small momentum transfers t and u in the framework of the quark-gluon model and Regge phenomenology. Our predictions reproduce very well the few data available at energies between 1.5 and 4.2 GeV, where our approach can be applied. Moreover, we found a good agreement also with the forward- and backward-angle data in the intermediate-energy region

[en] All the ²H(γ,p)n data in the energy range 20--440 MeV have been fitted to a simple phenomenological function. All differential cross-section data were used: The bremsstrahlung data were normalized to the total cross-section values obtained by fitting data provided by monochromatic photon beams. The results obtained give a good representation of the experimental points

[en] All existing data on the level densities, decay widths and lifetimes of excited nuclei have been analyzed in the framework of the statistical model in order to better determine the parameters of the phenomenological systematics of the nuclear level density. Data on level densities of several hundred nuclides obtained in the excitation energy range from 2 up to 20 MeV were used. The level densities of nuclei with large deformation (at the saddle point) have been studied by analyzing the data on the neutron emission and fission partial width ratio Γ_n/Γ_f, and the values of the fission barrier heights B_f, the level density parameters ratio a_f/a_n and the saddle point shell corrections δW_s.p. have been extracted. The influence of shell and collective effects on the level density and the decay widths of nuclei which have different excitation energies and deformations has been studied. (orig.)

[en] We have built and operated a system which monitors and controls the response of the 12 lead-glass and the 12 plastic scintillator detectors in the coincidence photon-proton (COPP) apparatus. We present here the detailed operation of the system and its performances during the experiment's runs. The gain control system, acting on the high-voltage values of the photomultiplier tubes, allows one to achieve a long term gain stability as good as 2% for each detector. (orig.)

[en] Differential cross sections for the d(γ,p)n reaction were measured at five laboratory angles, from 32deg to 130deg, and for seven photon energies (100, 120, 140, 180, 200, 220 and 255 MeV). A quasi-monochromatic photon beam was used and the photon spectrum was measured on-line with a pair spectrometer. The absolute normalization uncertainty is within ±5%. Data agree, taking into account total errors, with results of recent experiments with monochromatic photons. (author)

[en] An inclusive electron scattering experiment on ¹⁶O and ⁴⁰Ar is presented. The ADONE electron storage ring, a clustered jet-target and a BGO calorimeter to detect electrons were used. Spectra were collected at beam energies from 0.5 up to 1.5 GeV and at laboratory scattering angles from 32 degrees to 83 degrees. The Coulomb sum rule integrated in the quasi-elastic peak at 570 and 800 MeV/c momentum transfer was measured in ¹⁶O and our ⁴⁰Ar results were compared with the available data on ⁴⁰Ca. (author). Letter-to-the-editor

[en] Published in summary form only