Total cross sections of Re185 and Re187

A method is described, and results given, for measurements, made at the VVR-M reactor of the Institute of Physics of the Ukrainian Academy of Science, of the total neutron cross sections of the isotopes Re¹⁸⁵ and Re¹⁸⁷ in the resonance, thermal, and cold regions of the neutron spectrum. The cross section of these isotopes follow the 1/v law with good accuracy below 0.08 eV; however,the positive levels of Re¹⁸⁵ are responsible for only 56% of the total cross section in the thermal region, and those of Re¹⁸⁷ for only 3%. An analysis of the cross sections shows that the energy of the negative level in Re¹⁸⁷ closest to zero is 5 eV|e₀|10 eV; in Re¹⁸⁵, |E₀|10 eV.Translated from Atomnaya Énergiya, Vol. 19, No. 3, pp. 250–252, September, 1965     

Impact parameter method calculations for fully differential ionization cross sections

In this work, our previous fully differential ionization cross section calculations using the semiclassical, impact parameter method are improved by a new method suitable to calculate impact parameter values corresponding to different momentum transfers. This goal is achieved by two successive steps. First, using the transverse momentum balance different projectile scattering angles are calculated for the binary and recoil peak regions as a function of the transferred momentum. Then, by treating the projectile scattering as a classical potential scattering problem, impact parameters are assigned to these scattering angles. The new method, which no longer contains empirical considerations, is tested calculating by fully differential ionization cross sections for single ionization of helium produced by fast C⁶⁺ ions.     

Theoretical estimate of the fast-neutron fission cross sections of235,238U

Institute of Physics and Power Engineering. Translated from Atomnaya énergiya, Vol. 76, No. 3, pp. 201–205, March, 1994.     

Scattering of protons by hydrogen atoms at low energies: Phase shifts and differential cross sections

Phase shifts and differential cross sections for spin exchange (charge transfer) and total elastic scattering of protons by hydrogen atoms are presented for 36 and 38 values, respectively, of the collisional kinetic energy in the range 0.0001 to 10 eV (center of mass). The phase shifts are tabulated with a precision of six decimal digits. Each cross section is presented as a graph covering the complete angular range from 0 to π radians (in center-of-mass coordinates). The phase shifts were obtained via partial wave analysis within a modified Perturbed-Stationary-States theory by calculations based upon very accurate (nonrelativistic) internuclear potential energies for the 1Sσ_g and 2Pσ_u electronic states of H₂⁺. The cross sections demonstrate a transition from purely quantum behavior at very low energies (<0.1 eV) to semicllssical behavior at higher energies (>1 eV) in which protons scattered by spin exchange are angularly separated from those scattered without exchange. Thus the in-principle unobservable charge-transfer cross section becomes physically measurable at energies greater than about 1 eV.     

Stopping cross sections of liquid water for MeV energy protons

Cross sections for the stopping of swift protons in liquid water have been measured for the first time by using a liquid water jet target of 50 μm in diameter. The energy loss spectra of incident 2.0 MeV protons were measured at scattering angles of 5.0-50 mrad. Experimental energy loss spectra have been successfully reproduced by Monte Carlo simulation calculations (GEANT4.9.1.p02 toolkit) by taking account of multiple scattering of projectile ions inside the liquid water target. The present stopping cross sections are found to be considerably smaller than other standard stopping power data, revealing e.g. about 11% deviation from those of SRIM2003.     

1-2 MeV能区6Li(n,t)4He反应微分截面与截面的实验测量

利用屏栅电离室对1.05、1.54及2.25 MeV中子6Li(n,t)4He反应的微分截面与截面进行了实验测量.采用氚固体靶的T(p,n)3He反应产生准单能中子,用相对效率已知的BF3长中子管和238U裂变片相结合来测定绝对中子通量.将测量结果与已有数据进行了比较,1-2 MeV能区6Li(n,t)4He反应截面的分歧在一定程度上得到了澄清.