Themomentum distributions of deuterons and nucleons from the reaction 4 Не(γ, pn ) d induced by bremsstrahlung photons whose spectrum extends up to the endpoint energy of 150 MeV weremeasured by means of a diffusion chamber placed in a magnetic field. These measurements were performed in four photon-energy intervals for deuterons and in the energy range between 100 and 150 MeV for nucleons. Angular and energy correlations of nucleons were measured at photon energies in the interval between 50 and 70 MeV. The results obtained in this way were analyzed on the basis of the quasideuteron model. The probability for final-state nucleon–deuteron interaction was estimated.

The reaction of two-particles nitrogen nucleus photodisintegration with Li-7 and Be-7 in the final state are investigated using diffusion chamber, which is placed into the magnetic field and filled with 15% nitrogen and helium compound. Chamber was irradiated with gamma rays from electron accelerator. The method of extraction of the reaction from the background two-particle reactions with multi-charged ions in the final state was created. Differential, full and integral cross-section of the reaction were measured. The results were compared with experimental data, where the full isotope Be-7 output at N-14 photodisintegration reaction was measured.

Using a spectrometer based on a diffusion chamber, which is placed in the magnetic field, the He-4(gamma, pn)d reaction was researched in the energy range from the reaction threshold up to 100 MeV. Nucleons differential cross sections, angular and energy correlation functions of the reaction products were measured. The structure which wasn't observed previously is detected in the deuteron kinetical energies distribution of events. Possible gamma-quanta absorbtion by nucleus mechanisms are discussed.

The experimental research results for two reactions of photodisintegration of a carbon nucleus which proceed with the knocking out the nucleons from different shells are considered. The total cross-section dependence with respect to energy and dependence of expansion coefficients of the nucleon angle distributions by trigonometric functions on energy are compared. Both reactions have dependence non-regularities within the 34...44 MeV energy interval, it can be explained as a change of mechanism the nucleus absorbs a photon. It is shown that a joining of the quasideuteron mechanism has a identical energy threshold if nucleons are detached from the different shells of a carbon nucleus.

By exposing a diffusion chamber in a magnetic field to bremsstrahlung gamma-quanta with a maximum energy of 150 MeV, the partial channel of formation of a 8 Be nucleus excited up to an energy of 1.5 MeV in the C-12(gamma,n) (3)He2 alpha and C-12(gamma, p) (3)H2 alpha reactions has been studied. On the excitation curve for a system of two alpha-particles, a resonance structure with a maximum located at E-0 approximate to 0.72 MeV, possessing the width Gamma = 0.7 5 MeV, and identified as a ghost anomaly (GA) was revealed between the ground state and the first excited state of the Be-8 nucleus. The reactions were demonstrated to be of the sequential type of decay. After removal of a nucleon from the s-shell of a C-12 nucleus, the excited states of C-11 and B-11 nuclei are formed; the decay of those nuclei gives rise to the formation of a Be-8 nucleus, which decays afterwards into two alpha-particles. Possible mechanisms of gamma-quantum absorption by the carbon nucleus have been discussed.

The angular dependence of azimuthal asymmetry of cross sections for the 4He( γ → , p )T and 4He( γ → , n )3He reactions was measured at linearly polarized photon energies of 40, 60 and 80 MeV. With the data obtained as the basis and using the previously measured differential cross sections, a multipole analysis of the reactions was performed in the E1, E2 and M1 approximation. The cross sections for the multipole transition and their errors were estimated by multiply solving the set of equations that relate the Legendre coefficients to the multipole amplitude moduli. Cross sections for spin S = 1 transitions of the final-state particles were determined.

The four-particle photodisintegration of a carbon nucleus in the reactions 12 C( γ , p ) 3 H2 α and 12 C( γ , n ) 3 H2 α is investigated by a method that employs a diffusion chamber in a magnetic field. It is shown that these reactions proceed according a sequential-type scheme: excited states of 11 B and 11 C nuclei decay to weakly excited states of 8 Be, 7 Li, and 7 Be nuclei. It is concluded that nucleons are knocked out from the s shell. In the excitation curve for the 2 α system in the reaction 12 C( γ , p ) 3 H2 α , a resonance is found between the maxima corresponding to the ground and the first excited state of the 8 Be nucleus, and this resonance is identified as a ghost anomaly. The branching fractions of the decay modes are determined. The angular distributions of nucleons in the reaction c.m. frame are measured. The energy dependence of the asymmetry coefficient for the angular distributions is obtained. A fast increase in this coefficient is observed in the energy range 38–40 MeV. It is concluded that the asymmetry coefficient depends on the excitation energy of the final nucleus in the region of intermediate photon energies.

The experimental setup is described, and the angular dependence of the asymmetry Sigma(p,n)(theta) of the cross section for the reactions He-4(gamma, p)T and He-4(gamma, n)He-3 induced by 40-, 60-, and 80-MeV linearly polarized photons is measured. The asymmetry Sigma(p,n)(theta) calculated in the relativistic gauge-invariant approach is in satisfactory agreement with experimental data on this asymmetry, with the exception of the asymmetry of the cross section for the reaction (gamma, n) at E(gamma) = 60 MeV and theta = 90 degrees - 120 degrees. In the last case, the theoretical value is close to unity, while the experiment yields Sigma(n)(theta) = 0.47 +/- 0.18.

This paper presents the data on the angular dependence of the cross-section asymmetry of the {sup 4}He({gamma},n){sup 3}He and {sup 4}He({gamma},p){sup 3}H reactions measured with a 40 MeV linearly polarized photon beam of the Kharkov 2 GeV electron linac. We also give results of the multipole analysis of these reactions. (AIP).

We describe the experimental apparatus and present the results of measurement of the angular dependence {Sigma}({theta}{sub {ital N}}) of the asymmetry of the cross sections for the reactions {sup 4}He({gamma},{ital n}){sup 3}He and {sup 4}He({gamma},{ital p}){sup 3}H in a linearly polarized beam of {gamma} rays with energy 40 MeV. The results agree with a calculation taking into account the interaction of the {gamma} ray with a nucleon and the {ital A}=3 nucleus. A multipole analysis yields upper-limit estimates of the total cross section for magnetic-dipole absorption of {gamma} rays in these reactions.

This paper presents the data on the angular dependence of the cross‐section asymmetry of the 4He(γ,n)3He and 4He(γ,p)3H reactions measured with a 40 MeV linearly polarized photon beam of the Kharkov 2 GeV electron linac. We also give results of the multipole analysis of these reactions. (AIP).

The asymmetry of the cross sections for the (..gamma..,p) and (..gamma..,n) reactions in the two-particle disintegration of the /sup 4/He nucleus by linearly polarized ..gamma.. rays with an energy of 40 MeV has been measured for the first time. The asymmetry is pronounced for both of these reactions.