Measurement and simulation of the cross sections for nuclide production in natW and 181Ta targets irradiated with 0.04- to 2.6-GeV protons

The cross sections for nuclide production in thin ^natWand ¹⁸¹Ta targets irradiated by 0.04–2.6-GeV protons have been measured by direct γ spectrometry using two γ spectrometers with the resolutions of 1.8 and 1.7 keV in the ⁶⁰Co 1332-keV γ line. As a result, 1895 yields of radioactive residual product nuclei have been obtained. The ²⁷Al(p, x)²²Na reaction has been used as a monitor reaction. The experimental data have been compared with the MCNPX (BERTINI, ISABEL), CEM03.02, INCL4.2, INCL4.5, PHITS, and CASCADE07 calculations.     

Measurement and simulation of the cross sections for nuclide production in 56Fe and natCr targets irradiated with 0.04- to 2.6-GeV protons

The cross sections for nuclide production in thin ⁵⁶Fe and ^natCr targets irradiated by 0.04–2.6-GeV protons are measured by direct γ spectrometry using two γ spectrometers with the resolutions of 1.8 and 1.7 keV for the ⁶⁰Co 1332-keV γ line. As a result, 649 yields of radioactive residual product nuclei have been obtained. The ²⁷Al(p, x)²²Na reaction has been used as a monitor reaction. The experimental data are compared with the MCNPX (BERTINI, ISABEL), CEM03.02, INCL4.2, INCL4.5, PHITS, and CASCADE07 calculations.     

Measurement and simulation of the cross sections for nuclide production in 93Nb and natNi targets irradiated with 0.04- to 2.6-GeV protons

The cross sections for nuclide production in thin ⁹³Nb and ^natNi targets irradiated by 0.04- to 2.6-GeV protons have been measured by direct γ spectrometry using two γ spectrometers with the resolutions of 1.8 and 1.7 keV in the ⁶⁰Co 1332-keV γ line. As a result, 1112 yields of radioactive residual nuclei have been obtained. The ²⁷Al(p, x)²²Na reaction has been used as a monitor reaction. The experimental data have been compared with the MCNPX (BERTINI, ISABEL), CEM03.02, INCL4.2, INCL4.5, PHITS, and CASCADE07 calculations.     

Measurement and simulation of the cross sections for the production of 148Gd in thin natW and 181Ta targets irradiated with 0.4- to 2.6-GeV protons

The cross sections for the production of ¹⁴⁸Gd in ^natW and ¹⁸¹Ta targets irradiated by 0.4-, 0.6-, 0.8-, 1.2-, 1.6-, and 2.6-GeV protons at the ITEP accelerator complex have been measured by direct α spectrometry without chemical separation. The experimental data have been compared with the data obtained at other laboratories and with the theoretical simulations of the yields on the basis of the BERTINI, ISABEL, CEM03.02, INCL4.2, INCL4.5, CASCADE07, and PHITS codes.     

Reaction cross sections for 65 MeV protons on targets from 9Be to 208Pb

Reaction cross sections for 65.5 MeV protons have been measured for ⁹Be, ¹²C, ¹⁶O, ²⁸Si, ⁴⁰Ca, ^58,60Ni, ^{112.116.118.120.124}Sn, and ²⁰⁸Pb. The results are compared with optical model predictions using relativistic global potentials.     

Heavy fragment production cross sections from 1.05 GeV/nucleon 56Fe in C, Al, Cu, Pb, and CH2 targets

We have obtained charge-changing cross sections and partial cross sections for fragmentation of 1.05 GeV/nucleon Fe projectiles incident on H, C, Al, Cu, and Pb nuclei. The energy region covered by this experiment is critical for an understanding of galactic cosmic ray propagation and space radiation biophysics. Surviving primary beam particles and fragments with charges from 12 to 25 produced within a forward cone of half-angle 61 mrad were detected using a silicon detector telescope to identify their charge and the cross sections were calculated after correction of the measured yields for finite target thickness effects. The cross sections are compared to model calculations and to previous measurements. Cross sections for the production of fragments with even-numbered nuclear charges are seen to be enhanced in almost all cases.     

Cross sections for the production of Li and Be isotopes in carbon targets irradiated by 300 GeV protons

Cross sections for the production of Li and Be isotopes in carbon targets irradiated by 300 GeV protons have been measured by mass spectrometry. The results are compared with lower energy measurements and discussed in terms of the variation of the cosmic ray L/M ratio in this energy region.     

Measurement of cross sections for gamma transitions induced in excited nuclei by the interaction of 1.1-GeV protons with silicon nuclei

The cross sections for the production of excited nuclei were measured in the reaction ²⁸Si(p, xpyn)A* followed by a gamma transition to a state of lower excitation energy or to the ground state. The experiment was performed in an extracted proton beam from the accelerator of the Institute of Theoretical and Experimental Physics (ITEP, Moscow). The reaction in question was identified by a Ge(Li)-NaI(Tl) anticoincidence spectrometer that recorded prompt gamma radiation emitted by the excited final nucleus. The sensitivity of the experiment was 1.5 mb. The cross-section values were obtained for 24 gamma transitions in 17 nuclear products. The cross sections for spallation reactions were estimated. A comparison was performed with known experimental data and with the results of calculations by a semiempirical formula, as well as with the results obtained by simulating hadron interactions on the basis of the GEANT and INUCL codes.     

Fluctuations in the total cross sections of Y,Zr, La,Ce, Pr,Gd, Ho,Ta and Hg for 1.0 TO 2.0 MeV neutrons

Results of an analysis of the fluctuations observed in the neutron total cross sections of nine different nuclei in the energy range between 1.0 and 2.0 MeV are presented. It has been found that in general these may be explained to be due to fluctuations in the widths and spacings of the compound-nucleus level. The cross section data for some of the nuclei seem to indicate the presence of structures with widths much larger than the compound-nucleus width.     

Measurement of the ratio of total and differential cross sections on neutrons and protons for charged-current neutrino events

Charged-current neutrino interactions have been analysed in a sample of pictures from BEBC equipped with a TST. Using a method independent of both the neutrino flux and nuclear interaction corrections, the ratio R= σ_n/σ_p has been measured. The result is R=1.98±0.19 for the ratio of total cross sections. Bjorken x distributions for proton and neutron targets and for u and d quarks are compared.     

The total charge-changing cross sections and the partial cross sections of 56Fe fragmentation on Al,C and CH2 targets

The total charge-changing cross sections and the partial cross sections of ⁵⁶Fe fragmentation on polyethylene, carbon and aluminum targets at the highest energy of 496 A MeV are investigated using CR-39 plastic nuclear track detector. The total charge-changing cross-section for hydrogen target is calculated based on the results of polyethylene and carbon targets. It is found that the total charge-changing cross sections for fragmentation of ⁵⁶Fe on hydrogen, carbon and aluminum targets are independent on the beam energy in our studied energies, and are consistent with the predictions of Bradt–Peter semi-empirical formula, Nilsen parameterized formula, NUCFRG2 and QMSFRG theoretical simulation codes. The partial cross sections for projectile fragment production are independent on beam energy in our studied energies for each targets and do not show a significant even-odd effect.     

Fission of Pb nuclei induced by 0.5, 1.0, 1.5, 3.7 and 7.4 GeV protons in the volume of massive U/Pb and Pb targets

Experiments with relativistic protons accelerated at the Synchrophasotron LHE, Dubna, with energies of 0.5, 1.0, 1.5, 3.7 and 7.5 GeV hitting massive targets of (nat. U)/Pb and Pb were carried out using SSNTD during the years 1996–1999. The beam profiles and intensities of both primary particles and fast secondary neutrons were measured inside the massive cylinder blocks of Pb and U by counting fission fragment tracks due to the induced fission of Pb nuclei. The beam diameter typically increases by 20–30% at the depth 10 and 20 cm. With increasing the energy of protons the number of secondary neutrons increases with the depth of the target.

Further studies on beam profile measurements inside the massive heavy metal targets are discussed.     

Al production cross sections from the Na(α, n)Al reaction

Cross sections have been determined for the production of ^{26g, m}Al from the ²³Na(α, n) reaction. Total ²⁶Al production cross sections were obtained from measurements of the thick-target neutron yield. ^26mAl cross sections were measured using an activation technique. ^26gAl cross sections were deduced by subtracting the ^26mAl cross sections from the total (α, n) cross sections. The principle of detailed balance has been applied to the low-energy data to obtain cross sections for the astrophysically interesting ^26gAl(n, α₀)²³Na reaction. These results are compared with the results of Hauser-Feshbach calculations.     

Measurements of neutron yields and spatial distributions in U/Pb, Pb and Hg thick targets bombarded by 0.5 and 1.0 GeV protons

Measurements have been carried out on neutron yields and spatial distributions in U/Pb, Pb and Hg thick targets and the surrounding paraffin moderators bombarded by 0.533 and 1.0 GeV protons. CR-39 detectors were deployed on the surfaces of targets and moderators to record the neutrons produced in the targets. The measurements show that:

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Differential cross sections for the photoproduction of eta mesons from protons near 2 GeV

Differential cross sections for the process γp → pη have been measuredd at c.m. angles of 28°, 35° and 42° at incident energies between 2 GeV and 2.8 GeV. Data from an earlier experiment below 2 GeV have been re-analysed and corrected. The whole set of data is compared with the form (s?M²)² dσ/dt, which fits data at higher energies. There is good agreement above 2 GeV, particularly at the largest angle, but strong departures below.     

Total, partial, and electron-capture cross sections for ionization of water vapor by 20-150 keV protons

We present experimental results for proton ionization of water molecules based on a novel event by event analysis of the different ions produced (and lost). We are able to obtain mass analyzed product ion signals (e.g., H2O+, OH+, O+, O++, H+) in coincidence with the projectile analyzed after the collision, i.e., either being H+, neutral H after single electron capture during the ionization event, or H- after double electron capture. After proper calibration we are thus able to determine a complete set of cross sections for the ionization of a molecular target by protons including the total and the partial cross sections and in addition also the direct ionization and the electron capture cross sections.     

A dependence of the cross sections for the cumulative production of pions and protons in proton-nucleus and nucleus-nucleus interactions

The behavior of the inclusive cross sections for the cumulative production of π ^± mesons and protons in pA, DA, and ⁴HeA interactions is studied versus the atomic mass number of fragmenting nuclei. The primary-beam momenta were 4.5 GeV/c per nucleon. Secondary pions and protons were recorded with a fixed momentum of 0.5 GeV/c at an angle of 120°. Specifically, the experiment explored the fragmentation of D, He, ⁶Li, ⁷Li, C, Si, ⁵⁸Ni, ⁶⁴Ni, ⁶⁴Zn, ¹¹⁴Sn, ¹²⁴Sn, and Pb nuclei. The energy spectra of π ⁺ and π ^? mesons and protons with momenta in the range 0.3–0.7 GeV/c (the emission angle being 120°) were measured in an 8.9-GeV/c proton beam for Ni, Zn, and Sn isotopes. The special features in the behavior of the cross sections are found and discussed, and a comparison is drawn with the results of other studies.     

Double differential cross sections for (p,xn) reactions of64Zn,65Cu and89Y with 26MeV protons

Double differential cross sections for the inclusive production of neutrons from⁶⁴Zn,⁶⁵Cu and⁸⁹Y bombarded with 26.0 MeV protons have been measured with time-of-flight techniques. The data reduction is discussed with respect to the influence of background corrections in the continuous part of the spectra, and a short comparison with preequilibrium model calculations is presented, showing good agreement with predictions of both, the hybrid and the geometry-dependent hybrid model including multiple particle emission. The question of how to treat pairing remains open.