MeV In Agreement Research Articles

Decay scheme of Pr144

The decay of the 17.5 min Pr144 has been investigated with a scintillation spectrometer. The energy of the gamma transitions in the daughter nucleus Nd144 are found to be 2.18, 1.49 and 0.70 MeV in agreement with the measurements of other investigators. The ambiguities concerning the previously reported 2.8, 1.67 and 1.16 MeV gamma transitions are removed. A decay scheme is then proposed.

Backward π +p elastic scattering from a direct channel Δ δ resonance model

The available experimental data on backward π +p elastic scattering in the angular region of cosθ=-0.94 to cosθ = -1 for laboratory momenta of 400 MeV/ c to 4 GeV/ c are adequately explained by direct channel contributions of knowm I = 3 2 resonances. Comparison with the data requires positive parities for the I = 3 2 resonances at 2450 and 2850 MeV in agreement with Δδ Regge recurrence assignments.

The12C (γ, n)11C cross-section above the giant resonance

The cross-section for the reaction12C(γ, n)11C above the giant resonance has been measured up to 70 MeV of γ-ray energy. The Penfold and Leiss analysis gives a value of the integrated cross-section of (88 ± 7) mb MeV in agreement with the classical dipole sum rule; the contribution between 35 and 70 MeV is about 30 mb MeV,i.e. 34% of the measured integrated (γ, n) cross-section. A wide resonance at about 35 MeV mainly corresponding to 1s12/−11p1/2 transition predicted by the particle-hole calculations has been observed. There is also some evidence of structure at about 53 MeV.

Decay of neodymium 141

A report is given of the experimental study of the Nd141 activity resulting from 14 MeV neutron bombardment of Nd142. The Nd141 decay is found to take place mainly by electron capture with positon emission occurring approximately 3% of the time. Gamma rays are observed with energies of 1.30 MeV, 1.16 MeV, 1.13 MeV and 0.14 MeV. Evidence is found for a level in Pr141 at 1.13 MeV in agreement with previous studies of inelastically scattered deuterons.

ReactionC14(p, n)N14

The reaction ${\mathrm{C}}^{14}(p, n){\mathrm{N}}^{14}$ has been studied up to 5-Mev bombarding proton energy with good resolution using targets of high isotopic enrichment. Levels previously unseen in this reaction were found at proton energies of 3.19 Mev ($\ensuremath{\Gamma}=6$ kev), 3.38 Mev ($\ensuremath{\Gamma}=24$ kev), 3.63 Mev ($\ensuremath{\Gamma}=13$ kev), 3.89 Mev ($\ensuremath{\Gamma}=35$ kev), 4.19 Mev ($\ensuremath{\Gamma}=112$ kev), 4.24 Mev ($\ensuremath{\Gamma}=27$ kev), 4.61 Mev ($\ensuremath{\Gamma}=140$ kev), and 4.93 Mev ($\ensuremath{\Gamma}=106$ kev). Excitation curves at three angles in the region of 2.9-Mev proton energy show the effect of the previously known $J={\frac{3}{2}}^{\ensuremath{-}}$ ($\ensuremath{\Gamma}=80$ kev) resonance interfering with a level of opposite parity. Effects of the nearby $J={\frac{7}{2}}^{\ensuremath{-}}$ ($\ensuremath{\Gamma}=40$ kev) level are not seen, presumably due to the low penetrability of the outgoing $F$-wave neutron. The thresholds for the second and third neutron groups were investigated using a lithium iodide detector. A new threshold, that for production of the third neutron group, was measured to be 4.910\ifmmode\pm\else\textpm\fi{}0.008 Mev in agreement with the known energy of the second excited state in ${\mathrm{N}}^{14}$.

Beta Spectrum ofTh233

The beta spectrum of ${\mathrm{Th}}^{233}$ has been measured in a ring-focus solenoidal spectrometer and was not found to exhibit an anomalous shape, as had been previously reported. The end point is 1.23\ifmmode\pm\else\textpm\fi{}0.01 Mev in agreement with the earlier value. It is shown that ${\mathrm{Th}}^{233}$ decays predominantly to the ground state of ${\mathrm{Pa}}^{233}$. Halflife measurements yield a value of (22.4\ifmmode\pm\else\textpm\fi{}0.1) min for ${\mathrm{Th}}^{233}$, somewhat shorter than the previously reported values.

ReactionLi6(p, γ)Be7

The reaction ${\mathrm{Li}}^{6}(p, \ensuremath{\gamma}){\mathrm{Be}}^{7}$ has been investigated by using protons of energy 0.4 to 1 Mev incident on isotopically separated ${\mathrm{Li}}^{6}$ targets. Capture gamma radiation to the ground state and the 430-kev state in ${\mathrm{Be}}^{7}$ has been observed; some 62% of the transitions go to the ground state. The ratio of intensities does not change significantly with energy, nor with angle of observation at ${E}_{p}=750$ kev. The differential cross section with the counter at 90\ifmmode^\circ\else\textdegree\fi{} and ${E}_{p}=750$ kev is about 2\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}32}$ ${\mathrm{cm}}^{2}$/steradian. The combined angular distribution of the two gamma rays is $1+(1.05\ifmmode\pm\else\textpm\fi{}0.15){cos}^{2}\ensuremath{\theta}$ at ${E}_{p}=750$ kev. The $Q$ value for the reaction is 5.66\ifmmode\pm\else\textpm\fi{}0.03 Mev in agreement with that calculated from mass values.