Chromium and titanium isotopes produced in photonuclear reactions of vanadium, revisited

Photonuclear production yields of ^5^1Ti und ^5^1^,^4^9^,^4^8Cr from ^5^1V were redetermined for bremsstrahlung end-point energies (E"0) of 30 to 1000 or 1050 MeV with the aid of radiochemical separation of Cr. The yield curves for ^5^1Ti, ^5^1Cr, ^4^9Cr and ^4^8Cr show a clear evidence for two...
Ausführliche Beschreibung

Photonuclear production yields of ^5^1Ti und ^5^1^,^4^9^,^4^8Cr from ^5^1V were redetermined for bremsstrahlung end-point energies (E"0) of 30 to 1000 or 1050 MeV with the aid of radiochemical separation of Cr. The yield curves for ^5^1Ti, ^5^1Cr, ^4^9Cr and ^4^8Cr show a clear evidence for two components in the production process; one tor secondary-proton reactions at E"0 < Q"π and the other for photopion reactions, at E"0 > Q, Q"π being Q-values for (γ, π^+) and (γ, π^+ xn) reactions. The contributions of the secondary reactions for production of the Ti and Cr isotopes at E"0 > Q"π were then estimated by fitting calculated secondary yields to the observed ones at E"0 < Q"π, and found to be about 40%, 20%, 4% and 4% for ^5^1Ti, ^5^1Cr, ^4^9Cr and ^4^8Cr, respectively, at E"0 = 400 to 1000 MeV. The calculation of the secondary yields was based on the excitation functions for ^5^1V(n, p) and (p, x'n) calculated with the ALICE code and the reported photoneutron and photoproton spectra from ^1^2C and some other complex nuclei.The present results for ^4^9Cr are close to the reported ones, while the present ^4^8Cr yields differ by a factor of about 50. For the ^5^1Ti and ^5^1Cr yields, there are some discrepancies between the present and reported ones. The yield corrected for the secondaries, in units of μb/equivalent quantum, were unfolded into cross sections per photon, in units of μb, as a function ol monochromatic photon energy with the LOUHI-82 code. The results for the ^5^1Ti and ^4^9Cr are in disagreement in both the magnitude and shape with the theoretical predictions based on DWIA and PWIA. A Monte Carlo calculation based on the PICA code by Gabriel and Alsmiller does reproduce the gross feature of the present results. Ausführliche Beschreibung