Incident Deuteron Research Articles

Excitation functions for the radionuclide46Sc produced in the irradiation of 45Sc with deuterons and 6He

Results of the measurements of the excitation function in the deuteron-induced reaction 45Sc(d, p)46Sc have been obtained at the energy of incident deuterons up to 11.7 MeV. In addition, data for the 45Sc(d, t)44Sc reaction were obtained. The experiments were performed using the variable energy cyclotron U-120M (NPI, Řež) and the Electrostatic Generator EG-5 (FLNP, JINR). The cross sections of the induced activities were measured using the stacked-foil technique. The measured excitation functions were similar to those observed for the 45Sc(6He, 5He*)46Sc reaction, studied at the accelerator complex for radioactive beams DRIBs (FLNR, JINR). The maximum probability of producing 46Sc was also found close to the Coulomb barriers of these reactions. The compilation of available experimental data, obtained at deuteron and 6He-energies near the Coulomb barrier, showed that the values of the cross sections at the maxima of the excitation functions obtained in (d, p) reactions and the reactions for one-neutron pickup from the 6He projectiles have a different Z-dependence.

Relevance of d-D interactions on neutron and tritium production in IFMIF-EVEDA accelerator prototype

In the IFMIF-EVEDA accelerator prototype, deuterium is implanted in the components due to beam losses and in the beam dump, where the beam is stopped. The interaction of the deuterons with the deuterium previously implanted leads to the production of neutrons and tritium, which are important issues for radioprotection and safety analysis. A methodology to assess these production pathways in more realistic approach has been developed. The new tools and their main achievement are: (i) an “effective diffusivity coefficient” (deduced from available experimental data) that enables simulation of the diffusion phase, and (ii) the MCUNED code (able to handle deuteron transport libraries) allows to simulate the transport-slowdown of deuteron/tritium (to get the concentration profiles) and the neutron/tritium productions from d-Cu and d-D for up to 9MeV incident deuteron. The results with/without theses tools are presented and their effect on the relevance of d-D sources versus d-Cu is evaluated.

Experimental studies of neutron emission spectra in Li(d,xn) reactions for IFMIF

To improve the accuracy of the neutron emission data in the natLi(d,xn) reaction, which will be used as the neutron source in the International Fusion Materials Irradiation Facility (IFMIF), we measured the double-differential neutron emission cross-sections (DDXs) of the d-Li reaction at 25MeV at the cyclotron facility of Tohoku University. The DDXs were measured at ten laboratory angles between 0° and 110° by the time-of-flight method, using a beam-swinger system and a well-collimated neutron flight channel. We used a two-gain method to obtain over most of the energy range of secondary neutrons and reveal the shape of the overall emission spectra including the breakup peak of incident deuterons near half the incidence energy, and several peaks in the high-energy tail due to stripping reactions. The experimental results compared favorably with those obtained using the extended Serber model.

Improved deuteron elastic breakup energy dependence via the continuum-discretized coupled-channels method

Experimental elastic-scattering angular distributions for deuteron interaction with $^{63}\mathrm{Cu}$ and $^{93}\mathrm{Nb}$ targets are compared with calculations performed within the continuum-discretized coupled-channels (CDCC) method, in which coupling to breakup channels is explicitly taken into account. The calculated elastic breakup cross sections are compared with the predictions of an empirical parametrization for a wide range of deuteron incident energies. The good agreement between the calculations and the systematics at the energies where data are available indicates that the CDCC method permits a useful assessment of empirical parametrizations and provides useful guidance for the extrapolation of these parametrizations beyond the energies formerly considered.

Deuteron microscopic optical model potential

A deuteron microscopic optical model potential is obtained by the Green function method through nuclear-matter approximation and local-density approximation based on the effective Skyrme interaction. The microscopic optical model potential is used to calculate the deuteron reaction cross sections and the elastic scattering angular distributions for some target nuclei in the mass range $6\ensuremath{\leqslant}A\ensuremath{\leqslant}208$ with incident deuteron energies up to $200$ MeV. The calculated results are compared with the experimental data.

Neutron production from 7Li(d,xn) nuclear fusion reactions driven by high-intensity laser–target interactions

Numerical simulations of neutron production from deuterium–lithium nuclear fusion reactions have been performed. A set of differential cross sections for the 7Li(d,xn) reaction for incident deuteron energies of up to 50 MeV is assembled. The angular distribution of neutrons from a thick lithium target is simulated and benchmarked against experimental data. Two-stage neutron production from laser–target experiments has been studied as a function of laser intensity and energy. During the first stage a well collimated deuteron beam is generated using a high-intensity ultrashort pulse laser. During the second stage it is transported through a lithium target using a 3D Monte-Carlo ion beam–target deposition model. The neutron yield is estimated to be ∼108 neutrons J−1 laser energy. Some 1010 neutrons can be expected from a ∼100 J petawatt-class laser. For incident deuteron energies above 1 MeV the proposed scheme for neutron production from d–Li reactions is superior to that from d–d reactions, producing a collimated beam of neutrons with higher neutron yield.

Nuclear reactions and the double beta decay

Charge-exchange reactions of ( n , p ) and ( p , n ) types at intermediate energies are introduced as a tool for the study of nuclear matrix element in β β decay. Here, the ( n , p ) type reactions are realized through ( d , 2 He ) , where 2He refers to two protons in a singlet 1 S 0 state and where both of these are momentum analyzed and detected by the same spectrometer and detector. These reactions have been developed and performed exclusively at KVI, Groningen (NL), using an incident deuteron energy of 183 MeV. The ( 3 He , t ) reaction is of ( p , n ) type and was developed at the RCNP facility in Osaka (JP) at incident energies of 420 MeV. Using both reaction types one can extract the Gamow–Teller transition strengths B ( G T + ) and B ( GT − ) , which define the two “legs” of the β β decay matrix elements for the 2 ν β β decay. The high resolution available in both reactions allows a detailed insight into the excitations of the intermediate odd–odd nuclei and, as will be shown, some unexpected features are being unveiled.

New Approach for Evaluating Incomplete and Complete Fusion Cross Sections with Continuum-Discretized Coupled-Channels Method

We propose a new method for evaluating incomplete and complete fusion cross sections separately using the Continuum-Discretized Coupled-Channels method. This method is applied to analysis of the deuteron induced reaction on a 7Li target up to 50 MeV of the deuteron incident energy. Effects of deuteron breakup on this reaction are explicitly taken into account. Results of the method are compared with those of the Glauber model, and the difference between the two is discussed. It is found that the energy dependence of the incomplete fusion cross sections obtained by the present calculation is almost the same as that obtained by the Glauber model, while for the complete fusion cross section, the two models give markedly different energy dependence. We show also that a prescription for evaluating incomplete fusion cross sections proposed in a previous study gives much smaller result than an experimental value.

Pionic atom factory project in the RIBF

We are preparing for a high resolution spectroscopy of the 1s and 2s pionic states of 121Sn in the 122Sn(d,3He) reaction at the incident deuteron energy of ~500 MeV. The measurement will provide accurate information on the strong interaction between the pion and the nucleus, which leads to quantitative determination of the magnitude of the quark condensate at the normal nuclear density.

Exclusive measurement of two-pion production in the [formula omitted] reaction

The results from the first kinematically complete measurement of the d d → He 4 π π reaction are reported. The aim was to investigate a long standing puzzle regarding the origin of the peculiar ππ-invariant mass distributions appearing in double pion production in light ion collisions, the so-called ABC effect. The measurements were performed at the incident deuteron energies of 712 MeV and 1029 MeV, with the WASA detector assembly at CELSIUS in Uppsala, Sweden. We report the observation of a characteristic enhancement at low ππ-invariant mass at 712 MeV, the lowest energy yet. At the higher energy, in addition to confirming previous experimental observations, our results reveal a strong angular dependence of the pions in the overall centre of mass system. The results are qualitatively reproduced by a theoretical model, according to which the ABC effect is described as resulting from a kinematical enhancement in the production of the pion pairs from two parallel and independent N N → d π sub-processes.

Elastic Nd scattering at intermediate energies as a tool for probing the short-range deuteron structure

A calculation of the deuteron polarization observables A d y , A yy , A xx , A xz and the differential cross section for elastic nucleon-deuteron scattering at incident deuteron energies 270 and 880 MeV in lab is presented. A comparison of the calculations with two different deuteron wave functions derived from the Bonn-CD NN-potential model and the dressed-quark-bag model is carried out. A model-independent approach, based on an optical-potential framework, is used in which a nucleon-nucleon T matrix is assumed to be local and taken on the energy shell, but still depends on the internal nucleon momentum in a deuteron.

Cross section measurements of theB10(d,n0)C11reaction below 160 keV

New data were taken at the Triangle Universities Nuclear Laboratory to investigate the plausibility of using low energy deuterons and the $^{10}\mathrm{B}$$(d,n)$$^{11}\mathrm{C}$ reaction as a portable source of 6.3 MeV neutrons. Analysis of the data at and below incident deuteron energies of 160 keV indicates an ${n}_{0}$ neutron cross section that is lower than previous estimates by at least three orders of magnitude. In separate runs, deuterons with two different energies (160 and 140 keV) were stopped in a $^{10}\mathrm{B}$ target. The resulting ${n}_{0}$ neutrons of approximately 6.3 MeV were detected at angles between ${0}^{\ifmmode^\circ\else\textdegree\fi{}}$ and ${150}^{\ifmmode^\circ\else\textdegree\fi{}}$. The angle integrated yields were used to determine the astrophysical $S$ factor for this reaction assuming a constant value for the $S$ factor below 160 keV. The cross sections reported between 130 and 160 keV were calculated using the extracted value of the $S$ factor. The measured ${n}_{0}$ cross section is several orders of magnitude smaller than previous results, thus eliminating $^{10}\mathrm{B}$$(d,n)$$^{11}\mathrm{C}$ as a portable source of intense neutrons with low energy deuteron beams on the order of tens of microamps. In order to gain insight into the reaction dynamics at these low energies the cross section results have been compared with results from calculations using the distorted wave Born approximation (DWBA) and a detailed Hauser-Feshbach calculation performed by the authors. The angular distribution is consistent with the Hauser-Feshbach calculation suggesting a statistical compound nucleus reaction rather than a direct reaction.

Measurements of activation cross sections of (n, p) and (n, α) reactions in the energy range of 3.5–5.9 MeV using a deuterium gas target

Activation cross sections of (n, p) and (n, α) reactions were measured by means of the activation method in the neutron energy range of 3.5–5.9MeV using a deuterium gas target. The irradiated target isotopes were 27Al, 28,29Si, 41K, 51V, 61Ni, 65Cu, 64,67Zn, 69Ga, 79Br, 92Mo and 93Nb. The cross sections of the 29Si(n, p) 29Al, 67Zn(n, p) 67Cu, 69Ga(n, p) 69mZn, 79Br(n, p) 79mSe, and 69Ga(n, α) 66Cu reactions were obtained for the first time in the studied energy range. The d-D neutrons were generated by the deuterium gas target at the Van de Graaff accelerator (KN-VdG) at Nagoya University. All cross section values were determined relative to those of the 115In(n, n′)115mIn reaction. The activities induced by the low-energy neutrons were corrected. For the corrections, the neutron spectra and mean neutron energies at the irradiation positions were calculated taking into account the energy loss of incident deuterons, the angular differential cross section of the d-D reaction and the solid angle subtended by the sample. The systematics of the (n, p) reactions at the neutron energy of 5.0MeV in the mass range between 27 and 92 were proposed for the first time. This systematics can predict the cross sections within an accuracy of a factor of 1.6.

Evaluation of D(d,n) 3 He reaction neutron source models for BNCT irradiation system design

A mathematical method was developed to calculate the yield, energy spectrum and angular distribution of neutrons from D(d,n) 3 He (D-D) reaction in a thick deuterium-titanium target for incident deuterons in energies lower than 1.0MeV. The data of energy spectrum and angular distribution were applied to set up the neutron source model for the beam-shaping-assembly (BSA) design of Boron-Neutron-Capture-Therapy (BNCT) using MCNP-4C code. Three cases of D-D neutron source corresponding to incident deuteron energy of 1000, 400 and 150 keV were investigated. The neutron beam characteristics were compared with the model of a 2.45 MeV mono-energetic and isotropic neutron source using an example BSA designed for BNCT irradiation. The results show significant differences in the neutron beam characteristics, particularly the fast neutron component and fast neutron dose in air, between the non-isotropic neutron source model and the 2.5 MeV mono-energetic and isotropic neutron source model.

Performance of neutron polarimeter SMART-NPOL

The neutron polarimeter SMART-NPOL has been constructed at the RIKEN Accelerator Research Facility for measuring polarization correlations of proton–neutron systems. The SMART-NPOL system consists of 12 parallel neutron counter planes of two dimensionally position-sensitive plastic scintillators with a size of 60 × 60 × 3.0 cm 3 . Polarimetry measurements were made using the analyzing power of the H 1 ( n ⇒ , n ) H 1 reaction occurring in the plastic scintillators. The effective analyzing power of SMART-NPOL was measured with polarized neutrons from the zero-degree Li 6 ( d ⇒ , n ⇒ ) reaction with an incident deuteron energy of 135 MeV / A . The effective analyzing power thus obtained was 0.26 ± 0 . 01 stat ± 0 . 03 syst and the double scattering efficiency was 1.1 × 10 - 3 .

Characterization of a tunable quasi-monoenergetic neutron beam from deuteron breakup

A neutron irradiation facility is being developed at the 88-inch cyclotron at Lawrence Berkeley National Laboratory for the purposes of measuring neutron reaction cross sections on radioactive targets and for radiation effects testing. Applications are of benefit to stockpile stewardship, nuclear astrophysics, next generation advanced fuel reactors and cosmic radiation biology and electronics in space. The facility will supply a tunable, quasi-monoenergetic neutron beam in the range of 10–30MeV or a white neutron source, produced by deuteron breakup reactions on thin and thick targets, respectively. Because the deuteron breakup reaction has not been well studied at intermediate incident deuteron energies, above the target Coulomb barrier and below 56MeV, a detailed characterization was necessary of the neutron spectra produced by thin targets.Neutron time-of-flight (TOF) methods have been used to measure the neutron spectra produced on thin targets of low-Z (titanium) and high-Z (tantalum) materials at incident deuteron energies of 20MeV and 29MeV at 0°. Breakup neutrons at both energies from low-Z targets appear to peak at roughly half of the available kinetic energy, while neutrons from high-Z interactions peak somewhat lower in energy, owing to the increased proton energy due to breakup within the Coulomb field. Furthermore, neutron spectra appear narrower for high-Z targets. These centroids are consistent with recent preliminary proton energy measurements using silicon telescope detectors conducted at LBNL, though there is a notable discrepancy with spectral widths. Prospects for producing a tunable, quasi-monoenergetic neutron facility of 106–108n/cm2/s at LBNL are promising.

Single neutron pick-up on 104Pd

Low-lying levels of 103Pd have been investigated through the (d,t) reaction on 104Pd, at an incident deuteron energy of 15.0 MeV. Outgoing particles were momentum analyzed by an Enge magnetic spectrograph and detected in nuclear emulsion plates, with an energy resolution of 8 keV. Previous (d,t) work suffered from a much worse resolution than that here achieved. A partial analysis of the data obtained is reported, referring to six out of the fourteen scattering angles for which data were obtained. Angular distributions associated with eight of the thirteen levels seen up to 1.1 MeV of excitation have been compared to DWBA one-neutron pick-up predictions. Both, the attributed excitation energy values and the transferred angular momenta are in excellent agreement with the results of other kind of experiments, as tabulated by the Nuclear Data Sheets. Some peculiar structure characteristics, associated with the yrast 5/2+, 3/2+ and 7/2+ states found in the Ru chain could be recognized also in 103Pd, pointing to the possibility of a more global understanding of this transitional mass region.

Global deuteron optical model potential for the energy range up to 183 MeV

Based on the existing experimental data of elastic scattering angular distributions and nonelastic cross sections (i.e., total reaction cross sections) for incident deuteron, by using the modified code APMN, we obtain a new optimal set of global deuteron optical potential parameters, which can fit (or reproduce) the experimental data very well for almost all target nuclei ranging from $^{12}\mathrm{C}$ to $^{238}\mathrm{U}$ in the energy region below 183 MeV.

Effects of the projectile electronic structure on stopping parameters for nickel

The stopping powers of nickel foils for 1H+, 2H+ and 4He2+ ions have been accurately measured over the energy range E≈(0.166−2.725)MeV/amu. The data were compared to those reported in the literature and to values derived by the SRIM-2003 code. They were analysed in the framework of the modified Bethe–Bloch theory to extract the target mean excitation and ionisation potential, I, and the Barkas effect parameter, b. The values derived from the proton and the alpha particle data are {I=(311.11±2.61)eV, b=1.38±0.01} and {I=(276.12±2.84)eV, b=1.58±0.01}, respectively. They thus show opposite variations of the I and b parameters as the projectile charge increases, presumably due only to the incident ions electronic structure. Besides, the reduced stopping power data for incident deuterons show to be fully consistent with those for protons indicating no effect of the projectile isotopic structure on the target stopping parameters. These results are discussed in comparison with ones reported in the literature.

Spin-isospin excitations in the medium-mass nucleus Co58 investigated with the (d,2He) reaction

We have studied spin-isospin excitations in Co-58 via the (n,p) type Ni-58(d,He-2)Co-58 reaction at small angles and an incident deuteron energy of 170 MeV. An energy resolution of 130 keV, full width at half maximum, was obtained allowing the extraction of Gamow-Teller strength to 13 individual levels in Co-58 below an excitation energy of 4.1 MeV. These DeltaL=0 transitions were identified by comparing the measured angular distributions with distorted-wave Born approximation (DWBA) calculations. A multipole decomposition analysis based on those DWBA calculations allowed the determination of the fractions of the DeltaL=0, 1, 2 components in the excitation spectrum. The experimental results are in reasonable agreement with large-scale shell-model calculations.