M. L. Terranova

Photodisintegration of light and medium-weight nuclei at intermediate energies—III: Spallation of vanadium, manganese, iron and cobalt

Abstract Cross sections per equivalent quantum, in the energy range 0.3–1.0 GeV, have been measured for spallation residuals from 51V, 55Mn, natural Fe, and 59Co targets. Mean cross sections per photon have been deduced in this energy range and the data analysed in terms of charge-dispersion curves and mass-yield distributions. The mean cross sections per photon have also been compared with a semiempirical Rudstams formula. A satisfactorily good agreement has been found with the calculated yields within a factor of two.

Fission yields of209Bi andnatPb nuclei induced by photon beams of 226 MeV maximum energy from compton backscattered laser light

SummaryThe yields of the photofission reactions induced in209Bi andnatPb by quasi-monochromatic photon beam of 226 MeV maximum energy have been measured by using makrofol plates as solid-state detector of fission tracks and found to be (1.1±0.4) mb and (0.8±0.4) mb, respectively. The measured yields are compared with data of fission induced in the same targets by different photon beams.

Evaluation of Total Nuclear Photoabsorption Cross-Sections by the Modified Quasi-Deuteron Model

Levingers modified quasi-deuteron model has been used to analyse available experimental data on total nuclear photoabsorption cross-section in the mass range 7 ≤ A ≤ 238 and in the energy range (35 ÷ 140) MeV. It is shown that the measured cross-sections are successfully reproduced by the formula σT(Eγ) = LNZ/AσD(Eγ) exp [- D/E] with L = 6.1 ± 2.2 and D = 0.72A0.81.

Cross sections of (γ, xn) reactions in complex nuclei at intermediate energies☆

Cross sections per equivalent quantum, in the energy range 0.3–1.0 GeV, have been measured for 209Bi(γ, 2n), 209Bi(γ, 3n), 209Bi(γ, 4n), 59Co(γ, 2n), 509Co(γ, 3n), 59Co(γ, 4n) and 51V(γ, 3n) reactions. From the calculated mean absolute cross sections and the data already available in literature for (γ, xn) reactions (x ≥ 1), a cross section formula has been deduced which reproduces, within a factor of two, most of the experimental cross sections for target nuclei ranging between 9Be and 238U.

Photodisintegration of light and medium-weight nuclei at intermediate energies—V: Mass-yield dependence of true direct (γ,n) and (γ,p) reactions

Abstract The mass-yield dependence of ( γ , n ) and ( γ , p ) reactions in the photon energy range (0.2–1) GeV has been investigated. A Monte Carlo calculation for these reactions has been carried out to compare values of the measured cross sections with those arising from different models of interaction. Very good agreement was found between experiment and estimates based on a fast-step, direct character for the reaction mechanism. As a result of the analysis, N - and Z -dependences of mean cross sections are given for the ( γ , n ) and ( γ , p ) reactions. Agreement with a more sophisticated theory is also quite reasonable.

Analysis of fission and fragmentation events produced in Ag and Br nuclei by interaction of bremsstrahlung beams in the energy range (1.0÷5.5) GeV

SummaryNuclear emulsion plates Ilford-K0 exposed to (1.0÷5.5) GeV bremsstrahlung beams in order to study photoinduced break-up of Ar, Br nuclei have been processed to produce visible fission tracks for track analysis with optical microscope. Track-length distributions, angular distributions and angular correlations of the produced fragments obtained at six end-point bremsstrahlung energies are presented and discussed. The analysis of the data shows that the recorded events are produced by two different reaction mechanisms, namely fission and fragmentation. The absolute mean cross-sections per photon for fragmentation, binary and ternay fission of Ag, Br targets in the energy range investigated have been measured. Absolute mean cross-sections per photon and corresponding fissilities have been evaluated for binary fission of Ag and Br and compared with literature data.

Photodisintegration of light and medium-weight nuclei at intermediate energies—VI: Yields of π-mesons from (γ, πχ) reactions on nuclei

Abstract The mass-yield dependence of π-meson photoproduction from complex nuclei has been investigated in the energy range from threshold up to 1 GeV. From both the available experimental data and the results of the present calculation, evidence for a volume production of photopions has been found. Agreement with recent theories is quite satisfactory.