A. Fantoni

Measurement of the total cross section for 238U photofission in the nucleon resonance region

Abstract We present the results of the photofission cross section for 238 U measured between 200 and 1200 MeV. In the ‡ region our results agree with existing data on the total photoabsorption cross section, while at higher energy they show no evidence of the higher nucleon resonances, clearly seen in the photon absorption on the photon, and a damping of the absolute value.

Absolute total photoabsorption cross sections on nuclei in the nucleon resonance region

Abstract We present the results of an absolute measurement of the photoabsorption cross section on Li, C, Al, Cu, Sn, and Pb between 300–1200 MeV. In the Δ region our results confirm that the strength is conserved, while in the higher resonances region they show a 7–15% damping and a possible mass-number dependence of the photoabsorption cross section.

Quasi-elastic and inelastic inclusive electron scattering from an oxygen jet target

Abstract The results of an experiment on inclusive electron scattering from an oxygen jet target, performed in a wide range of energy and momentum transfer covering both quasi-elastic and Δ(1232) resonance regions, are reported. In the former region the theoretical predictions, obtained including effects of nucleon-nucleon correlations in both initial and final states, give a good description of the experimental data. In the inelastic region a broadening as well as a damping of the resonant part of the cross section with respect to the free nucleon case is observed. The need of more detailed calculations including nuclear structure effects on the electroproduction cross section of nucleon resonances is highlighted.

Absolute measurement of the total photoabsorption cross section for carbon in the nucleon resonance region

Abstract We present the results of an absolute measurement of the total nuclear photoabsorption cross section for carbon in the higher nucleon resonance region. In the Δ region our results agree with existing data, while at higher energies they show a damping in the excitation of the higher nucleon resonances, clearly seen in the photon absorption on proton and deutron.

PERFORMANCE OF THE ELECTROMAGNETIC CALORIMETER OF THE HERMES EXPERIMENT

Abstract The performance of the electromagnetic calorimeter of the HERMES experiment is described. The calorimeter consists of 840 radiation resistant F101 lead-glass counters. The response to positrons up to 27.5xa0GeV, the comparison between the measured energy and the momentum reconstructed from tracking, long-term stability, hadron rejection and neutral meson invariant mass reconstruction are shown.

Performance of F101 Radiation Resistant Lead Glass Shower Counters.

Abstract The performance of F101 lead glass as a Cherenkov radiation material was studied. A 3 × 3 array of 9 × 9 cm2 and 50 cm length counters showed an energy resolution of ≈5.0% E(GeV) , good linearity in the energy range from 1 to 25 GeV and π − e rejection of ≈4 × 10−4.

Inclusive electron scattering from an oxygen and argon jet target

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.

Simulation of photon-nucleon interactions Part II. ν photoproduction with a 4π BGO calorimeter

Abstract We simulate an experiment of ν photoproduction on the nucleon performed with a 4 π BGO electromagnetic calorimeter and a Compton backscattering tagged beam of 1.5 GeV maximum energy to extract information on background suppression and trigger settings. The simulation is possible by the application of an event generator that reproduces the photon-nucleon interaction from the pion threshold up to 4 GeV.

The response of a BGO scintillation detector to 100–500 MeV kinetic energy pions, protons and deuterons

Abstract The light response of pions, protons and deuterons with respect to electrons of the same energy is measured in a BGO calorimeter using the inclusive 16 O(e, e′), 16 O(e, π), 16 O(e, p) and 16 O(e, d) reactions. An average 5% quenching is found in the 100–500 MeV energy range of this experiment.

The Frascati tagged photon beam from a molecular beam radiator

We describe the new monochromatic photon beam obtained at Frascati by tagging the bremsstrahlung, on a molecular beam radiator, of the electrons circulating in the Adone storage ring. The tagging system installed in one ring dipole, consists of two scintillation counter arrays defining 76 channels of 0.9% resolution (FWHM) at 1500 MeV. The system can tag photons at rates up to 5×107 s−1 in the range 200–1200 MeV.