Deuteron Energy Research Articles

A Monte Carlo model for low energy D–D neutron generators

Deuteron–deuteron (D–D) fusion reactions are foreseen for the next stage fusion reactors. A computational model is developed for simulating the neutron production by accelerating deuterons with energy less then 10 MeV onto solid targets containing deuterium. It requires the specification of the beam and target characteristics (e.g. deuterons energy, deuterium atomic fraction). The model is implemented in the subroutines of the MCNPX and MCNP5 codes, which need so far to be recompiled. The deuterons are transported inside the solid target by a Monte Carlo method. The neutrons are generated with the angle – energy distribution as defined by the laws and nuclear data for the deuteron–deuteron reaction in the ENDF/B-VII.0 library. The sensitivity studies on the input parameters of the D–D model are presented. The D–D source model is finally validated by an experiment, which has been performed by the FNG team at the IRMM with a high energy resolution detector. The results of the simulations indicate that the source model may be useful for the evaluation of the D–D neutron source term and associated uncertainties in experimental facilities.

The study of the [formula omitted] reaction at 500 MeV of the deuteron energy at ITS Nuclotron

The experiment on dp non-mesonic breakup at Internal Target Station at Nuclotron-M is presented. The first results on the study of the dp-breakup reaction with 500 MeV unpolarized deuteron beam are discussed. Selection procedure of useful events for the d p → p p n reaction with the registration of two protons is shown.

Quasi-free inclusive processes in the two-particle splitting of tritons by deuterons with an energy of 37 MeV

The d + t → d + d + n reaction was experimentally and theoretically investigated at an incident deuteron energy of 36.9 MeV. The experiment was performed on the U-240 isochronous cyclotron at the Institute for Nuclear Research, National Academy of Sciences of Ukraine. Inclusive spectra of deuterons and their angular distributions in the range of 15° ≤ θd ≤ 52° were measured. Experimental spectra and angular distributions of the final deuterons from the d + t → d + d + n reaction are satisfactorily described in a diffraction approximation that considers interaction in the final state and the correct asymptotic of the wave function of colliding nuclei. The scattered deuterons are the main contributors to the cross section (up to 70–90%), while the deuterons from tritons can be seen well only at low and high energies, at the edges of the spectra.

On the possibility to measure the imaginary part of the spin-dependent amplitude of zero-angle coherent elastic scattering in a spin-filter experiment with an unpolarized proton beam interacting with a polarized deuterium target

As deuterons pass through an unpolarized target, there appear the phenomena of spin rotation (oscillation) and spin dichroism of deuterons; both phenomena are the manifestation of the deuteron birefringence effect. The magnitude of the effect is determined by the refractive index of deuterons in matter, which depends on the spin-dependent part d1 of the amplitude of zero-angle coherent elastic scattering of the deuteron by the nucleus. Spin dichroism is determined by the imaginary part of this amplitude, and in view of the optical theorem, by the total scattering cross-section, which is different for different spin states of the deuteron. The phenomenon of spin dichroism of deuterons results in the fact that after passing through the target, the initially unpolarized deuteron beam acquires tensor polarization proportional to the difference in the total cross-sections of scattering of deuterons with different spin states by the nucleus. The stated difference was first measured for deuterons with energies up to 20 MeV, where the phenomenon of deuteron spin dichroism was experimentally revealed, and the deuteron tensor polarization was measured. The phenomenon of spin dichroism, i.e., the production of tensor polarization was also observed at high deuteron energy. In the present report we discuss the possibility that the imaginary part of the amplitude d1 of deuteron scattering by the proton may be determined experimentally by measuring the rate of the decrease in the intensity of an unpolarized proton beam in a storage ring as the beam passes through a tensor-polarized deuterium target.

Cross section measurements of the 6Li(d,α 0) 4He reaction

Differential cross-section measurements of the 6Li(d,α 0) 4He reaction have been performed for deuteron energy between 900 and 2000 keV in steps of 25 keV. The reaction α particles were detected at four backward angles from 140° to 170° in steps of 10°. A qualitative discussion of the observed variations in the reaction cross sections through the influence of resonances in the d + 6Li compound system is presented. The results are also compared to existing data, when present, and are validated through benchmarking experiments using high-purity, thick, mirror-polished natural LiF and LiAlO 2 targets.

ΔE-E detector for proton registration in nonmesonic deuteron breakup at the Nuclotron internal target

A design for a ΔE-E detector to investigate deuteron breakup in the Nuclotron-M internal target in a deuteron energy interval of 300–500 MeV is presented. The high-voltage power supply system of the PMT-63, which is based on the computer-controlled Wenzel Electronik module, is briefly described. A light-emitting diode (LED) monitoring system for the ΔE-E detector is considered. The results of testing the ΔE-E detector using cosmic muons and deuteron beams of the Nuclotron are presented.

RESCATTERING EFFECTS IN DEUTERON-PROTON ELASTIC SCATTERING AT INTERMEDIATE ENERGIES

The deuteron-proton elastic scattering is considered at the deuteron energies from 500 up to 2000 MeV. The multiple-scattering-expansion technique is applied to evaluate the reaction amplitude. The one-nucleon-exchange, single scattering and double scattering contributions are taken into account. Also, some relativistic effects are included into consideration. The obtained results are compared with the experimental data both for the differential cross section and polarization observables.

ISOSPIN SYMMETRY BREAKING AND BRANCHING RATIO IN THE DEUTERON REACTIONS AT VERY LOW ENERGIES

The target-material dependence of the neutron-proton branching ratio and breaking of the isospin symmetry in the the 2H(d, n)3He and 2H(d, p)3H reactions at very low deuteron energies have been investigated. Angular distributions and total cross sections of the proton and neutron mirror channels have been measured for nuclear reactions taking place in different metallic environments. For Sr , Li , Na targets, we have found a first evidence for an alteration of the neutron-proton branching ratio and angular anisotropy of the neutron channel. We discuss various theoretical approaches explaining isospin mixing effects both in gas and metallic target experiments including a deuteron polarization in the crystal lattice. Direct reaction contribution has been calculated within the zero range distorted wave Born approximation (DWBA).

Saturated ablation in metal hydrides and acceleration of protons and deuterons to keV energies with a soft-x-ray laser

Studies of materials under extreme conditions have relevance to a broad area of research, including planetary physics, fusion research, materials science, and structural biology with x-ray lasers. We study such extreme conditions and experimentally probe the interaction between ultrashort soft x-ray pulses and solid targets (metals and their deuterides) at the FLASH free-electron laser where power densities exceeding 10(17) W/cm(2) were reached. Time-of-flight ion spectrometry and crater analysis were used to characterize the interaction. The results show the onset of saturation in the ablation process at power densities above 10(16) W/cm(2). This effect can be linked to a transiently induced x-ray transparency in the solid by the femtosecond x-ray pulse at high power densities. The measured kinetic energies of protons and deuterons ejected from the surface reach several keV and concur with predictions from plasma-expansion models. Simulations of the interactions were performed with a nonlocal thermodynamic equilibrium code with radiation transfer. These calculations return critical depths similar to the observed crater depths and capture the transient surface transparency at higher power densities.

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.

Correlation Analysis of Intense and High-Energy Deuteron Beam, Pinch Images, and Neutron Yield

The time-integrated imaging of pinched plasma column in the NX2 plasma focus device is performed using a general-purpose digital SLR camera with neutral density filters (ND 0.9). Although it is very simple, some useful information is obtained from the pinch phase of plasma focus device, and the images are compared with the neutron yield, electron, and ion beams produced in the compressed plasma column. The correlation between the pinch images, the range of deuteron energies, and the optimum neutron condition shows two regimes of plasma focus performance: high-pressure regime for maximum neutron yield production and low-pressure regime for high-energy ion (and electron) beam production.

Magnetic spectrometry of high energy deuteron beams from pulsed plasma system

A detailed and precise study of high energy deuteron beams from a plasma focus device shows that they follow a non-power law distribution, unlike most of the other works. This is in agreement with our previous studies using a direct and unambiguous diagnostic of the activation yield-ratio technique. It is possible that the E−n dependence effectively terminates at some maximum deuteron energy. The experimental results show that the spectrum increases to very high energies whereas the power law fit fails. A unique feature of the magnetic spectrometry experimental arrangement, in this work, is that the pinhole holder also functions as a Faraday cup for time-resolved measurements of the deuteron beam.

Propagation effects on fusion neutron generation in the Coulomb explosion of deuterated methane clusters

In this paper, fusion neutron yields from the Coulomb explosion of (CD4)N clusters under the irradiation of an intense femtosecond laser pulse is optimized by controlling the propagation of the laser pulse in a cluster jet. A correlated study of fusion neutron yields, kinetic energies of deuterons, together with the plasma channels diagnosed by a pump–probe interferometer, is performed. It has been found that by controlling the focal position related to the cluster jet, the plasma defocusing effect can balance with the tight focusing effect of the laser pulse induced by an off-axis parabolic mirror, and results in a cylindrical-shaped and relatively narrow plasma channel crossing the gas jet. The most energetic deuterons and the maximum yields of fusion neutrons are produced at the same time. For better understanding of the experimental results, numerical simulations for the nonlinear propagation of the femtosecond laser pulse in (CD4)N gas-cluster jets are performed. Simulated results show that plasma defocusing and laser attenuation play dominant roles in this case of optimization.

T(d, p)tn reactions at a deuteron energy of 37 MeV

Inclusive spectra of protons from T(d, p) reactions were measured in the angular range 15° ≤ θp ≤ 52° at energies Ed ≈ 36.9 MeV. Broad maxima in the medium region of the proton energy spectra from deuteron breakup in a field of tritium nuclei are adequately described in the diffraction approximation by taking into account final state interactions. A description of the high- and low-energy regions of spectra requires consideration of the contributions from the production and decay of 4H* intermediate resonances and 4He* resonance decay, respectively.

Design a 10 kJ IS Mather Type Plasma Focus for Solid Target Activation to Produce Short-Lived Radioisotopes 12C(d,n)13N

A 10 kJ (15 kV, 88 μF) IS (Iranian Sun) Mather type plasma focus device has been studied to determine the activity of a compound exogenous carbon solid target through 12C(d,n)13N nuclear reaction. The produced 13N is a short-lived radioisotope with a half-life of 9.97 min and threshold energy of 0.28 MeV. The results indicate that energetic deuterons impinging on the solid target can produce yield of \( \langle y\rangle \) = 6.7 × 10−5 with an activity of A = 6.8 × 104 Bq for one plasma focus shut and Aν = 4 × 105 Bq for 6 shut per mint when the projectile maximum deuterons energy is Emax = 3 MeV.

Efficient production of 100 keV deuterons in deuterium gas puff Z-pinches at 2 MA current

Deuterium gas puff experiments were carried out on the S-300 Z-pinch at the Kurchatov Institute in Moscow. Gas puffs imploded onto the axis before a current peak at about 100 ns. Fusion neutrons were generated after the gas puff implosion during global expansion of a plasma column. Neutron emission lasted on average 35 ± 5 ns (full width half maximum, FWHM). In the downstream direction (on the Z-pinch axis behind the cathode), a mean neutron energy was 2.6 ± 0.1 MeV. Side-on neutron energy spectra peaked at 2.40 ± 0.05 MeV with about 600 ± 150 keV FWHM. A broad width of side-on neutron spectra implied a high radial component of deuteron velocities. An average kinetic energy of fast deuterons, which produced fusion neutrons, was 150 keV. A peak neutron yield reached a value of 6 × 1010 on a current level of 1.5 MA. It was by one order higher in comparison with other deuterated loads used on the same current generator. On the basis of experimental observations, we concluded that a total energy of deuterons accelerated to fusion energies was above 1.5 kJ. It is more than 15% of the energy input into a plasma. Therefore gas puff Z-pinches seem to be not only powerful sources of x-ray radiation but also efficient sources of 100 keV deuterons. Such a result is consistent with high neutron yields observed on the Angara Z-pinch and plasma foci with similar currents.

Influence of laser frequency chirp on deuteron energy from laser-driven deuterated methane cluster expansion

The simulations of three-dimensional particle dynamics are carried out to investigate the Coulomb explosion dynamics of deuterated methane clusters under the irradiation of an ultrashort intense laser pulse. The final kinetic energy of deuterons produced from the cluster explosion is calculated as a function of the pulse width, the laser intensity and the pulse chirp. It is found that the deuteron energy obtained in an intense laser pulse with negative chirp is higher than that with positive chirp, which agrees qualitatively with the experimental results reported by Fukuda et al. [Y. Fukuda et al., Phys. Rev. A 67, 061201 (2003)].

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.

Deuteron energy of 15 MK in ultra-dense deuterium without plasma formation: Temperature of the interior of the Sun

Deuterons are released with kinetic energy up to 630 eV from ultra-dense deuterium as shown previously, by Coulomb explosions initiated by ns laser pulses at ⩽ 10 11 W cm − 2 . With higher laser intensity at < 10 14 W cm − 2 , the initial kinetic energy now observed by TOF-MS with variable acceleration energy is up to 1100 eV per deuteron. This indicates ejection of one deuteron by Coulomb repulsion from two stationary charges in the material. It proves a full kinetic energy release of 1260 eV or a deuteron temperature of 15 MK, similar to the temperature in the interior of the Sun. Plasma processes are excluded by the sharp TOF peaks observed and by the slow signal variation with laser intensity. Deuterons with even higher energy from multiple charge repulsion are probably detected. D + D fusion processes are expected to exist in the ultra-dense phase without plasma formation.

Effects ofθon the deuteron binding energy and the triple-alpha process

We study the effects that a non zero strong-CP-violating parameter theta would have on the deuteron and diproton binding energies and on the triple-alpha process. Both these systems exhibit fine tuning, so it is plausible that a small change in the nuclear force would produce catastrophic consequences. Such a nuclear force is here understood in the framework of an effective Lagrangian for pions and nucleons, and the strength of the interaction varies with theta. We find that the effects are not too dramatic.