Yield Of Deuterons Research Articles

Production of protons, deuterons, and tritons from carbon bombarded by 175 MeV quasi mono-energetic neutrons

We have measured double-differential yields of protons, deuterons, and tritons produced from carbon induced by 175 MeV quasi mono-energetic neutrons using the MEDLEY setup at the TSL neutron beam facility. The measured data are used for benchmarking of a high-energy nuclear data file, JENDL/HE-2007, and both intra-nuclear cascade (INC) model and quantum molecular dynamics (QMD) calculations.

Laser Plasma Heavy Ion Source Using Thin-Foil Target with Micro Tips

A target for a laser plasma ion source is improved by adding micro tips to a polytetrafluoroethylene thin foil that originally has a fibrous microstructure. C 6+ ions, deuterons, and protons are generated by irradiation of the target with laser pulses whose maximum intensity was 4.8×10 18 W/cm 2 . The additional micro-tip structure clearly increases the yields of deuterons and C 6+ ions, although that of the protons was not altered. The maximum energies of all the ion species are almost the same between the new and the conventional targets. They were ∼0.9, ∼1, and ∼6 MeV for the protons, deuterons, and C 6+ ions, respectively.

The ( π+,pd) and ( π+,dd) reactions on light nuclei at 100 and 165 MeV incident pion energies

The ( π +,pd), and ( π +,dd) reactions on 6Li and 12C targets were investigated with pions of 100 and 165 MeV kinetic energy. The experimental apparatus employed for this work is characterized by good energy resolution (<3%, ΔE/ E) and angle definition ( Δθ=1.6°), and the measurements span a large fraction of the final-state particle phase space. Results are compared to extensive Monte Carlo simulations in order to investigate the role of single-step and multistep absorption processes in these nuclei. In comparison with previously published ( π +,pp) data on the same targets and at the same beam energies, specific kinematic regions were identified in which the neutron hard pickup process n+p→d dominated the observed deuteron yield. The contribution of direct quasitriton absorption is significant only at 100 MeV.

ENTROPY PRODUCED IN 35MeV/u40Ar+197Au HEAVY ION REACTIONS

Light charged particles emitted from the reactions of 35MeV/u 40Ar+197Au are measured experimentally. A new observable,R=d/(d+t+3He+4He), which is defined as the reduced yield of deuterons, has a monotone relation with the entropy and it is independent of the breakup density (ρ/ρ0) and N/Z of the system. The entropy values are extracted by using several methods which use the d/p ratios,dlike/plike ratios, reduced yield of isotope deuterons R and the reduced multiplicity of charged particles Mred, respectively. The entropy values from the reduced yield of isotope deuterons R and the reduced multiplicity of charged particles Mred are nearly the same. These methods can be used in low beam energy heavy ion reactions. The charged particles emitted in rear angles are mainly from an equilibrium-state source with temperature about 4.7±1.2MeV, which are extracted from the double isotope yields ratios, and entropy S/A=2.5±0.5.This implies that the Break-up density is slightly less than 0.1(ρ/ρ0).

Proton and deuteron production in Au+Au reactions at11.6A GeV/c

Proton and deuteron distributions from 11.6A GeV/c Au + Au collisions measured by the E802 Collaboration in experiment E-866 are presented. The invariant yield of protons and deuterons is studied as a function of the transverse mass for different cuts of rapidity and centrality. At low mt−m0 the proton and deuteron invariant spectra deviate from a single exponential shape. The average mt as function of centrality and rapidity is used to explore the effect of collective transverse flow in the reaction. The ratio of the deuteron to squared proton yield as a function of transverse momentum, rapidity, and centrality is used to probe the coalescence model of deuteron production. This ratio is constant as a function of rapidity only for the most central cuts and decreases with the centrality for every rapidity cut. The ratio of the differential cross section of the deuteron to the squared differential cross section of the proton, for the most central cut, is not constant as a function of mt−m0.

The light yield response of NE213 organic scintillators to charged particles resulting from neutron interactions

The n- γ discrimination by the charge integration method has been used with a NE213 liquid cell associated with a specific photomultiplier Philips XP4512B. Such a device, which is part of the DEMON array (French abbreviation for DEtecteur MOdulaire de Neutrons), permitted us to identify up to six high energy neutron reaction channels in an organic scintillator. Through the analysis of recoil charged-particle spectra, light yields of protons, deuterons, tritons and alphas were deduced. Experimental results were fitted by the method of least squares to the two parametric formulae proposed respectively by Birks and Chou. Depending on the type of the detected charged particles, the KB and C parameters are extracted and compared to some values reported in the literature.

Differential cross section for n-p elastic scattering in the angular region 50 degrees< theta *

The differential cross section for n-p elastic scattering at 459 MeV in the c.m. angular region 50\ifmmode^\circ\else\textdegree\fi{}${\mathrm{\ensuremath{\theta}}}^{\mathrm{*}}$180\ifmmode^\circ\else\textdegree\fi{} has been measured with high statistical precision and good relative accuracy. The uncertainty in the absolute normalization (based on the simultaneously measured yield of deuterons from the np\ensuremath{\rightarrow}d${\mathrm{\ensuremath{\pi}}}^{0}$ reaction) was initially estimated to be \ensuremath{\sim}7%. The results agree well with back-angle data obtained independently at LAMPF but less well with results from Saclay and the Princeton-Pennsylvania Accelerator and, except for a normalization difference of 10%, are fairly well represented by a phase-shift fit. The pole-extrapolation method of Chew was used to extract the pion-nucleon coupling constant ${\mathit{f}}^{2}$ from the back-angle portion of the data. The value obtained, ${\mathit{f}}^{2}$=0.069, is somewhat smaller than the values 0.0735--0.0790 obtained from analyses of pion-nucleon scattering, tending to confirm the need for an upward renormalization of the angular distribution by \ensuremath{\sim}10%.

Neutron-charged-particle correlations in the 3.8 MeV per nucleon 16O+12C and 13.4 MeV per nucleon 16O+27Al reactions.

Neutron--light-charged-particle (LCP) and LCP-LCP correlation functions were measured for the 215 MeV $^{16}\mathrm{O}$${+}^{27}$Al reaction, together with the neutron-proton correlation function for the $^{16}\mathrm{O}$${+}^{12}$C reaction at ${\mathit{E}}_{\mathrm{lab}}$=60.5 MeV. The np and pp correlation data are compared with the predictions of the Koonin model and a semiclassical evaporation model. Both models provide an excellent fit to the np data, while the pp data are not reproduced as well. Production yields of singlet deuterons, ground state $^{5}\mathrm{He}$ and $^{5}\mathrm{Li}$, and $^{6}\mathrm{Li}$ nuclei in the 2.186 MeV state were obtained from the coincidence data, and a nuclear temperature of T=2.${0}_{\mathrm{\ensuremath{-}}0.6}^{+0.8}$ MeV for the $^{16}\mathrm{O}$${+}^{27}$Al compound system was determined from the ratio of singlet to ground state deuteron emission, after corrections for sequential emission and noncompound deuteron production. This temperature value is well below the Fermi gas model estimate, and a similar result is observed for the $^{16}\mathrm{O}$${+}^{12}$C compound system.

Deuteron and entropy production in relativistic heavy ion collisions.

Employing an extended version of the Boltzmann-Uehling-Uhlenbeck equation, we present simulations of the reaction 800 MeV/nucleon Ca+Ca. Deuteron spectra are calculated from the model without ad hoc assumptions. Absolute values of the proton and deuteron spectra are in good agreement with experiment. The dependence of the total deuteron yield on the nuclear equation of state is investigated and found to be weak. Both entropy and freeze-out density are strongly dependent on impact parameter. This suggests, in particular, that the freeze-out density has no physical meaning. Methods for calculating entropy are discussed and numerically compared.

Deuteron emission from a plasma and a vacuum arc formed on exposure of a deuterated cathode to laser radiation

A study was made of deuteron emission from a vacuum arc plasma stimulated by the action of laser radiation on the surface of zirconium deuteride. A family of dependences of the deuteron yield on the laser energy El and on the energy deposited in the vacuum arc E was obtained in the range El=1—25 mJ, E=0—400 mJ. A correlation was established between the deuteron formation processes in the electrode spots of the vacuum arc and in a laser plasma due to the dependence of the arcing conditions on the laser energy. It is found that an energy an order of magnitude higher was dissipated in the formation of a single deuteron in the electrode spots of the arc compared with that dissipated in the formation of a deuteron in a laser plasma.

Differential cross section for n-p elastic scattering in the angular range60°&lt;θ*&lt;180°at 801.9 MeV

The differential cross section for n-p elastic scattering at 801.9 MeV has been measured with high statistical precision and good relative accuracy over the angular range $60\ifmmode^\circ\else\textdegree\fi{}&lt;{\ensuremath{\theta}}^{*}&lt;180\ifmmode^\circ\else\textdegree\fi{}$. The absolute normalization is based on the simultaneously observed yield of deuterons from the $\mathrm{np}\ensuremath{\rightarrow}\mathrm{d}{\ensuremath{\pi}}^{0}$ reaction and is good to 7%. A nearly monoenergetic neutron beam, produced by proton bombardment of a liquid-deuterium target, was directed through a liquid-hydrogen target. The angle, velocity, and momentum of charged particles ejected from the target were measured in a magnetic spectrometer equipped with multiwire proportional chambers and timing scintillators. The results are in good agreement with earlier Saclay and LAMPF data and include an angular region not covered before. The pole-extrapolation method of Chew was used to extract a value ${f}^{2}=0.075\ifmmode\pm\else\textpm\fi{}0.005$ for the pion-nucleon coupling constant which is in agreement with accepted values, thus providing evidence for the accuracy of the shape and normalization of the angular distribution.

Differential cross section forn−pelastic scattering in the angular range51°&lt;θ*&lt;180°at 647.5 MeV

The $n\ensuremath{-}p$ elastic differential cross section in the angular range $51\ifmmode^\circ\else\textdegree\fi{}&lt;{\ensuremath{\theta}}^{*}&lt;180\ifmmode^\circ\else\textdegree\fi{}$ at 647.5 MeV has been measured with high statistical precision, good relative accuracy, and absolute normalization of 7% estimated accuracy (based on the observed yield of deuterons from $\mathrm{np}\ensuremath{\rightarrow}d{\ensuremath{\pi}}^{0}$). A monoenergetic neutron beam bombarded a liquid hydrogen target, and the protons and deuterons ejected from the target were detected by a multiwire proportional chamber spectrometer which measured their momentum, angle, and mass. The results resolve discrepancies between previous measurements of this observable, and are in reasonable agreement with Saclay data at large angles, and with a phase shift fit. Evidence for accuracy of the shape of the angular distribution is provided by the good value obtained for the pion-nucleon coupling constant (${f}^{2}=0.0759\ifmmode\pm\else\textpm\fi{}0.0030$) when the pole-extrapolation method of Chew is used to extract ${f}^{2}$ from this shape.NUCLEAR REACTIONS $^{1}\mathrm{H}(n, p)n$, ${T}_{n}=674.5$ MeV; measured $\frac{d\ensuremath{\sigma}}{d{\ensuremath{\Omega}}^{*}}$ vs ${\ensuremath{\theta}}^{*}$ for $51\ifmmode^\circ\else\textdegree\fi{}&lt;{\ensuremath{\theta}}^{*}&lt;180\ifmmode^\circ\else\textdegree\fi{}$.

Contributions of elastic, inelastic and absorptive breakup to the inclusive deuteron spectrum of the reaction 28Si( 3He, d) at E 3 He = 52 MeV

Deuteron-proton coincidence data from the reaction 28Si + 3He at E3 He = 52 MeV show contributions from elastic, inelastic and absorptive breakup. The latter process accounts for about 75% of the inclusive continuum deuteron yield at θ d = 10°. Systematics of these mechanisms are presented.

Charged particle emission from the capture of negative pions: energy spectra, LET distributions and W-value

By using various combinations of Si and CsI(Tl) detectors, the counter telescope was able to measure yields of protons, deuterons, tritons and helium nuclei down to 2 MeV and heavier nuclei down to 5 MeV. Targets of graphite, water, muscle-equivalent solution and rigid bone substitute were used, and data were taken at a scattering angle of 90 degrees at both the peak and the plateau of the depth-dose distribution and additionally at 45 degrees in the plateau. A W-value for a chamber at the peak containing nitrogen is calculated to be 35.8 eV per ion pair, indicating that an ionisation chamber calibrated against low LET radiation will underestimate the peak pion dose by 3.5%. Initial secondary particle spectra and dose: LET distributions are calculated from the measured yields.

Measurement of oxygen and nitrogen profiles in steel

A combined technique utilizing both Rutherford backscattering (RBS) and (d, p) reactions has been used to measure concentrations and depth profiles of oxygen and nitrogen in steel surfaces. The samples were exposed to erosive flows of burning propellant gases with widely varying flame temperatures. A deuterons beam of 0.665 MeV energy was used to perform the experiments. A high-resolution silicon surface barrier detector at 160° was used to detect both protons from the (d, p) reactions on oxygen and nitrogen and deuterons elastically scattered from the iron. Pulse pileup rejection with about 75 ns resolving time was needed to separate the 16O(d, p 1) peak from the leading edge of the deuteron yield curve. The use of deuteron backscattering in determining total concentrations and depth profiles of surface contaminants is described. Surface roughness effects on the RBS distributions have been considered and have been shown to be negligible. Oxygen and nitrogen concentrations and depth profiles in steel surfaces exposed to propellant burns have contributed to the understanding of hot gas steel erosion processes.

Quasi-elastic electron scattering (e, e′p) and (e, e′d) from 6Li in a coincidence experiment

Coincidence cross sections for the reactions 6Li(e, e′p) and 6Li(e, e′d) have been measured in the region of quasi-elastic scattering. Using incident electrons of 2.5 and 2.7 GeV, the four-momentum transfers to the proton were 6.6 fm −2, 10.0 fm −2 and 11.6 fm −2. The proton coincidence data agree with shell-model distributions assuming a Woods-Saxon potential and including short-range nucleon-nucleon correlations. The best fit to the deuteron coincidence data is obtained with a cluster wave function for the p-nucleons and a harmonic oscillator wave function for the s-nucleons taking into account the deuteron yield from the s-shell. The ratio of the deuteron cross section from 6Li divided by the elastic e-d scattering cross section depends only slightly on the four-momentum transfer and has a value of ≈ 2.

Isobaric-spin violation in the reactionB10(d,d′)B10

The reaction $^{10}\mathrm{B}(d,{d}^{\ensuremath{'}})^{10}\mathrm{B}$ was investigated to determine the isobaric-spin violation in exciting the lowest $T=1$ state of $^{10}\mathrm{B}$ at an excitation energy of 1.74 MeV. The extent and nature of the isobaric-spin-forbidden reaction was obtained by measuring yield curves at laboratory angles of 30, 45, and 77\ifmmode^\circ\else\textdegree\fi{}, using deuteron bombarding energies from 5 to 12 MeV and at 140\ifmmode^\circ\else\textdegree\fi{} from 6.5 to 16 MeV. Simultaneously, data were obtained on the nearby isobaricspin-allowed $T=0$ state at 2.15 MeV. Generally, broad structure dominates the excitation functions at all angles but tends to disappear at higher bombarding energies. Angular distributions of deuterons leading both to the $T=0$ and $T=1$ states were obtained at five bombarding energies between 6.5 and 12.0 MeV. The angular distributions both for the forbidden ($T=1$) and allowed ($T=0$) state are characterized by a trend to forward peaking with increasing bombarding energies although much less so for the $T=1$ state. The total cross sections were measured, and the ratios of the forbidden yield to allowed yield were found to decrease linearly from 0.69% at 6.5 MeV to 0.16% at 12 MeV. In an attempt to describe the angular distributions in terms of a direct-reaction mechanism, distorted-wave Born-approximation (DWBA) calculations were performed assuming collective excitations for the residual nucleus. No clear physical interpretation could be derived from these calculations. Indications are that the reaction $^{10}\mathrm{B}(d,{d}^{\ensuremath{'}})^{10}\mathrm{B}$ proceeds through states very high in the compound nucleus $^{12}\mathrm{C}$, where the isobaric-spin violation originates in Coulomb mixing of $T=1$ and $T=0$ states of the same spin and parity. In view of the very small yield of deuterons leading to the lowest $T=1$ state in $^{10}\mathrm{B}$, and in view of the background difficulties anticipated and experienced, a specialized charged-particle detection system was used, consisting of a position-sensitive gas proportional counter mounted on the focal surface of a broad-range magnetic spectrograph. This constitutes the first observation of the lowest $T=1$ state in $^{10}\mathrm{B}$ by the present reaction.

Deuteron Production in Nuclei by Protons of from 1 to 3-BeV

The deuteron yield and momentum spectrum for targets of Be, C, Cu, and Pb bombarded by 1-, 2-, and 3-BeV protons from the Cosmotron has been found at angles of 0, 17, and 32\ifmmode^\circ\else\textdegree\fi{}, using a magnetic spectrometer and time-of-flight telescope. The results cannot be explained in terms of a simple pickup, evaporation, or nucleon-nucleon statistical production process. Two other models involving two-stage processes have been proposed, namely, the indirect pickup process and a model in which nuclear matter "catalyzes" the coalescing of two cascade nucleons into a deuteron. Our results show that, at higher momenta in the deuteron spectrum, agreement can be obtained with the cascade theory. At the lower end of the momentum spectrum, deuterons may arise by the indirect pickup process.

Photodisintegration of Be 9

The spectra of photoprotons and α-particles from the Be 9(γ, p)Li 8 and Be 9(γ, n)Be 8∗→2α reactions are investigated with the aid of nuclear photoplates in a magnetic field. It is shown that the ( γ, p) reaction excitation function plotted by the energy spectrum of protons under the assumption that the recoil nucleus Li 8 is produced in the ground state is in good agreement with the excitation functions measured by the β − activity of the residual nucleus Li 8. The data on photoprotons agree with the available calculations of the “direct” photoemission of nucleons from the nucleus. It is shown that the intensity of ( γ, n) processes with the production of Be 8 in the second excited state 4 + roughly equals the overall intensity of the ( γ, n) processes with the production of Be 8 in states with E Be 8 ∗ from 16.08 to 22.06 MeV. A comparatively high ratio of the yield of deuterons to that of protons ( Y d / Y p = 0.20±0.10 at 3.7≦ E p , E d≦14.2 MeV) is measured. The cross section for the reactions accompanied by deuteron emission is estimated to account for 6 to 7% of the total cross section for the absorption of γ quanta with energies from 16.7 to 35 MeV.

Deuteron and α-particle production in carbon and polyethylene by 26.6 GeV/c protons

The production of deuterons in p-p collisions has been investigated by comparing the yield of deuterons from carbon and polyethylene targets exposed to the 26.6 GeV/c circulating proton beam of the CERN proton synchrotron. The deuterons were observed at 11.25° l.s. The yields from CH2 and C were normalized to the same number of interactions in carbon. These were monitored by counting the α-particles produced. The measurements were performed with deuterons having momenta of 1550, 1480 and 700MeV/c. There was no evidence of deuteron production from hydrogen within the accuracy of the experiment. An upper limit of 34 μb/(sr GeV/c) for the cross-section for producing deuterons in p-p collisions has been established with a 98% confidence level. This small value, although not in contradiction with the statistical calculations, strongly indicates the nuclear origin of the majority of the deuterons observed at our angle in high-energy collisions.