[en] A new generation of accelerators with a 100% duty factor beam in combination with the tagging of bremsstrahlung photons with high energy resolution δE/sub γ//Eγ≤10/sup -3/-10/sup -4/ and moderate fluxes (N/sub γ/(ΔE/sub γ/≤0.1E/sub o/ ≅10/sup 7//sec) makes possible new kinds of experiments for photopion production on the nucleon as well as on complex nuclei. Recent review covers the theoretical as well as the experimental situation. The main purpose of this paper is to show on a few examples the present situation in order to demonstrate the physics motivation and to compare the methods of the past with the possible methods of the future

No abstract available

[en] An intense circularly polarised γ -beam interacts with a cooled antiproton beam in a storage ring. Due to spin-dependent absorption cross-sections for the reaction γ+ anti p→π^-+ anti n a built-up of polarisation of the stored antiprotons takes place. Figures of merit around 0.1 can be reached in principle over a wide range of antiproton energies. In this process polarised antineutrons with polarisation P_barn succeeds 70% emerge. The method is presented for the case of a 300 MeV/c cooled antiproton beam. (orig.)

[en] Calculations based on a two-nucleon (n-p) absorption mechanism show that the form factor of the residual nucleus plays an important role in determining the shape of the photo-production cross section in a wide energy range 60 MeV < or = E/sub γ/ < or = 300 MeV

No abstract available

[en] In this report the absorption mechanism of photons (Esub(γ) >= 50 MeV) and pions will be investigated. Despite the different interaction force similar kinematic conditions are imposed on the absorption process. (orig./HSI)

[en] An experimental investigation of the reaction mechanism of (γ,n) and (γ,p)-reactions for photoenergies Esub(γ) > 60 MeV has been made. The results support models in which the photon is absorbed predominantly by neutron-proton pairs. (orig.)

[en] The photon reaction mechanisms in the intermediate energy range of 50 MeV<=EsUb(γ)<--150 MeV is discussed. Investigation of nuclei with photons and electrons possesses has the advantage that it is relatively easy to calculate the effects of these particles on charges and motion of the charges within a nucleus. It is shown that for the (γ, n) and (γ, p) processes the reaction mechanism may be interpreted in the quasideuteron model. In graphic form are shown the transitions in ¹⁶O and differential cross sections for ¹⁶O(γ, n)¹⁵O, and ¹⁶O(γ, p)¹⁵N reactions. It is concluded that: 1) in the 40 MeV<=Esub(γ)<=140 MeV energy range the total absorption cross section on nuclei can be described rather well by the qUasiteuteron model; 2) the absorption mechanism for the (γ, p) and (γ, n) reactions is mainly like the (γ, np) process - the photon gets absorbed on a neutron-proton pair. The absorption differential cross sections as a function of momentum transfer (energy, emission angle) is mainly determined by the formfactor

No abstract available

[en] Three classes of coincidence measurements are discussed: electron scattering, tagged bremsstrahlung (e,e'γ) where e' and x are detected, and correlated products (γ,xy) where the γ's are from bremsstrahlung. The nuclear physics motivation for doing coincidence measurements is discussed. Some common features of the reactions are mentioned as are factors affecting count rate limitations. Mainly considered is the presentation of a variety of examples from previous work. Sometimes counting rates from typical experimental arrangements are estimated. The aim is to provide a rough classification of types of measurements into feasibility classes. 23 references