Incident Deuteron Research Articles

2.217 MeV state inAr37

Cross section and vector analyzing power data for the 2.217 MeV state in $^{37}\mathrm{Ar}$ have been measured via the ($d,p$) reaction at an incident deuteron energy of 11 MeV. Distorted wave Born approximation analysis of the data establishes the spin parity of this relatively weak state as 7/${2}^{+}$. The data are fairly well reproduced by the calculations indicating that the one-step process plays a dominant role in populating the state in the ($d,p$) reaction. The spectroscopic factor for the state is found to be 0.04\ifmmode\pm\else\textpm\fi{}0.01. Model calculations indicate that two-step and compound nuclear processes have negligible effects on the conclusions.[NUCLEAR REACTIONS $^{36}\mathrm{Ar}(\stackrel{\ensuremath{\rightarrow}}{d},p)$, $E=11.0$ MeV; measured $\ensuremath{\sigma}(\ensuremath{\theta})$, $i{T}_{11}(\ensuremath{\theta})$. Deduced $J$, $\ensuremath{\pi}$, $S$. DWBA analysis.]

Finite-range DWBA analyses of [formula omitted]3He) reactions on 64Zn at Ed = 13 MeV

Exact finite-range DWBA analyses of ( d, t ) and ( dd , 3He) reactions have been performed for an 64Zr target at an incident deuteron energy of 13.0 MeV, leading to the ground states of the residual nuclei. The microscopic overlap functions for (d, t) and (d, 3He) systems obtained by using the Phillips triton wavefunctions have been used as projectile form factors into the calculation. The results are compared with zero-range DWBA calculations taking the finite-range effects into account by means of a local energy approximation. The results obtained by finite-range and zero-range calculations for differential cross sections as well as vector and tensor analysing powers are compared with the experimental data. The range of validity of the local energy approximation is discussed.

Neutron Polarization Measurements Using the Pulsed-Polarized Proton and Deuteron Beams at TUNL

Nanosecond wide pulses of polarized protons or deuterons at a repetition rate of 4 MHz are now routinely available for studying interactions involving outgoing neutrons. Up to 90 nA of protons and 200 nA of deuterons have been observed on target. Our first experiments involved the determination of the analyzing power Ay(?) for a few (p,n) and (d,n) reactions using conventional neutron time-of-flight detection. A major program for observing polarization effects in neutron elastic scattering has been initiated. The source of polarized neutrons for this program is the 2H(d,n) 3He reaction which yields a neutron beam having 90% of the polarization of the incident deuterons.

A study of the second-order processes in the elastic scattering of polarized deuterons

Angular distributions for the differential cross sections σ 0( θ) and the vector analyzing powers iT 11( θ) for 76, 78, 80, 82Se( d , d) scattering at 12 MeV incident deuteron energy, have been analyzed using a coupled-channel Born approximation. Two-step scattering processes involving inelastic excitations and single-neutron transfer reactions, have been included in the analysis. Detailed study of these processes has been carried out in order to determine their relative strengths and their parameter dependence. Excitation of 2 1 + states is found to dominate over all other second-order processes considered here and it has a strong influence upon the elastic scattering.

H−andD−production by backscattering from alkali-metal targets

Measurements have been made of the total backscattered ${\mathrm{D}}^{\ensuremath{-}}$ and ${\mathrm{H}}^{\ensuremath{-}}$ yields from thick, clean targets of Cs, Rb, K, Na, and Li, bombarded with ${\mathrm{H}}_{2}^{+}$, ${\mathrm{H}}_{3}^{+}$, ${\mathrm{D}}_{2}^{+}$, ${\mathrm{D}}_{3}^{+}$ with incident energies from 0.15 to 4.0 keV/nucleus. All of the measurements were made at background pressures less than ${10}^{\ensuremath{-}9}$ Torr, and the alkali-metal targets were evaporated onto a cold substrate ($T\ensuremath{\sim}77$ K) in situ to assure thick, uncontaminated targets. For each target, the ${\mathrm{H}}^{\ensuremath{-}}$ and ${\mathrm{D}}^{\ensuremath{-}}$ yields exhibited maxima (as high as 0.08 per incident proton and deuteron) at incident energies between 0.3 and 1.4 keV/nucleus. For both hydrogen and deuterium incident at any energy, the negative-ion yield decreases in going from Cs to Li in the order given above. Also, a definite isotope effect was observed for every target used, with the ${\mathrm{H}}^{\ensuremath{-}}$ yield peaking at a lower incident energy than the ${\mathrm{D}}^{\ensuremath{-}}$ yield and in most cases, the maximum ${\mathrm{H}}^{\ensuremath{-}}$ yield was higher than the maximum ${\mathrm{D}}^{\ensuremath{-}}$ yield. Measurements of the ${\mathrm{D}}^{\ensuremath{-}}$ yield as a function of Cs coverage were also made for ${\mathrm{D}}_{3}^{+}$ bombarding a Ni substrate. The ${\mathrm{D}}^{\ensuremath{-}}$ yield maximized at or near the coverage at which the surface work function reached a minimum.

Deuteron induced fission in 233U

The relative independent yields of Rb, Cs, and In from 233U(d,f) reaction were obtained at incident deuteron energies of 18, 31, and 44 MeV. From these mass distributions, the numbers of neutrons emitted per fission event were obtained and the charge division mechanism was investigated. Results indicated that within the energy region studied, the charge division process remained essentially the same as that for low energy events. The relatively larger widths of Cs distributions are explained in terms of dual stability zones around N = 82 and N = 86–88.

The 40A (d, p) Reaction and States in 41A

Cross-sections angular distributions for the reactions 40A (d, p) have been measured at an incident deuteron energy of 3.5 MeV and compared with OWBA and Hauser-Feshbach (HF) calculations. Spectroscopic factors and ln Values of orbital angular momentum neutron transferred have been deduced for most of the levels observed, namely the ground state, the 167, 516, 1035, 1354, 1869, 2398, 2695, 2733, 2890, 2949, 3010, 3285, 3327 and 3430 keV states. Three not previouslv reported states in 41A have been identified at (1564 ± 4) keV, (2360 ± 5) keV and (3926 ± 5) keV. The cross-sections corresponding to these states are very small in (d, p) reactions.

Experimental study and baryonic exchange interpretation of the reactionH2(d, n)He3in the intermediate energy region

We present a complete set of eight differential cross sections of the reactions $^{2}\mathrm{H}(d, n)^{3}\mathrm{He}$ and $^{2}\mathrm{H}(d, p)^{3}\mathrm{H}$ in the 0-60\ifmmode^\circ\else\textdegree\fi{} c.m. angular range for incident deuteron momenta between 1.1 and 2.5 GeV/c. A simple phenomenological interpretation of the energy dependence of the total cross section ${\ensuremath{\sigma}}_{T}$ and of $\frac{d\ensuremath{\sigma}}{\mathrm{dt}}$ at fixed $t$ shows, in the reaction, the contribution of a nucleon exchange process to which we must add a mechanism implying the ${\ensuremath{\Delta}}_{33}$ resonance excitation in the direct channel.

Deuteron break-up in the fields of nuclei at 56 MeV

Abstract Proton continuum spectra induced by 56 MeV deuterons have been measured for 14 elements ranging from 12C to 209Bi. Each spectrum shows a prominent bump at forward angles due to the break-up of the incident deuteron. The peak energy of the bump is about half the deuteron energy for light elements and increases slightly for heavier elements. Projectile break-up calculations reproduce well the spectral shapes and the angular dependence of the bump spectra. The characteristics of the bump spectra are determined by the proton momentum distribution in the deuteron. The break-up cross section increases with target mass and is nearly proportional to ( A 1 3 + 0.8) 2 . The target mass dependence indicates that all partial waves smaller than the grazing angular momentum contribute to the deuteron break-up cross section at this energy. The total break-up cross section amounts to 24–35% of the deuteron total reaction cross section.

Experimental and theoretical study of continuous proton spectra from high-energy deuteron induced reactions

Inclusive proton spectra were measured from 80 MeV deuteron-induced reactions on 27Al, 93Nb and 197Au targets. At forward angles the spectra exhibit broad deuteron break-up peaks centered around one-half of the incident deuteron energy for all the nuclei studied. Double-differential as well as angle-integrated cross sections in the bump region are well reproduced by calculations in the framework of the DWBA approach to break-up taking elastic and inelastic reactions of the neutron with the target nucleus into account. Like the observation made in case of low-energy deuteron break-up as well as in high-energy alpha break-up, the inelastic break-up is found to be a dominant reaction mode at this higher deuteron energy also. The preequilibrium contributions to the outgoing proton spectra have also been calculated. The analysis of the experimental data has been discussed in the light of these two different reaction mechanisms. It is found that these two reaction mechanisms put together provide a good overall description of the experimental proton spectra.

A study of the 91Zr(d, p) 92Zr reaction using vector-polarized deuterons

Differential cross sections and vector analyzing powers were measured for the 91Zr( d , d) 91Zr and 91Zr( d , p) 92Zr reactions at an incident deuteron energy of 12 MeV. Deuteron optical-model parameters were determined from an analysis of the elastic data. Comparison of the proton data to DWBA predictions showed that the DWBA does not quantitatively reproduce the measured analyzing powers, hence empirical analyzing power calibration curves were required to analyze the data. New spectroscopic information about the configurations of the excited states in 92Zr has been determined and is compared to the results of previous experiments as well as a shell-model calculation. The results of this experiment are in quantitative agreement with the predictions of the shell-model calculation for most of the transitions although some discrepancies do exist.

Two-step mechanism in deuteron polarisation

An unusual mass dependence of the vector analysing powers iT11( theta ) observed experimentally for the 76,78,80,82Se(dpol,d) elastic scattering at 12 MeV incident deuteron energy is now explained as being due mainly to the contributions from a two-step scattering process via the first Jpi =21+ excited states.

Study of the structure of the low-lying levels of 29Si via the 28Si(fx285-1)d, pγ) reaction and multi-step reaction calculations

The structure of the low-lying levels of 29Si has been studied by means of the 28Si( d , pγ) reaction. Previously measured differential cross-section and analyzing-power data are compared to results of multi-step reaction calculations. Proton-γ angular correlation data, initiated both with an unpolarized and with a polarized incident deuteron beam, are presented, and are also compared with the results of reaction calculations. The reaction trajectories assumed for the calculations are based on particle-core coupled wave functions for the 29Si levels. The analyzing-power and correlation data are found to exhibit considerably greater sensitivity to the details of the wave functions than do the differential cross-section data. Reasonable representations of the forward angle data are generally achieved.

The differential cross section and polarization quantities in the 4He(d, p)n 4He and 2H(α, n)p 4He reactions

The differential cross section and the polarization quantities ( T 11, T 20, T 21, T 22, P γ' ) in the deuteron breakup reaction by an α-particle are calculated in the framework of the recently developed three-body model. All values are discussed under the incomplete kinematical condition. All polarization quantities are caused by the difference of the potential between p 3 2 and p 1 2 waves of the N-α interaction. Results of the calculation are compared with the available measurement of (i) the differential cross section and the deuteron vector analysing power in the 4He( d , p)n 4He reaction and (ii) the differential cross section and neutron polarization in the 2H(α, n )p 4He reaction. The agreement with experiment is very satisfactory in each case. Among the tensor analysing powers of the deuteron the absolute value of T 20 is very large. Observables at the FSI peak corresponding to 5He g.s. are discussed systematically in the energy region of 5.4–20 MeV of the incident deuteron in the 4He(d, p)n 4He reaction. Although the differential cross section is not sensitive to the energy of the three-body resonance, the polarization quantities T 11, T 20, P γ' are quite sensitive to it.

Azz(0°)for the charge-symmetricHe3(d→,p)He4andH3(d→,n)He4reactions below 6.75 MeV

The tensor analyzing power of ${A}_{\mathrm{zz}}(0\ifmmode^\circ\else\textdegree\fi{})$ has been measured for the charge symmetric $^{3}\mathrm{He}(d,p)^{4}\mathrm{He}$ and $^{3}\mathrm{H}(d,n)^{4}\mathrm{He}$ reactions as a function of incident deuteron energy from 0.24 to 6.75 MeV. The measurements were performed in a nearly simultaneous fashion to ensure that a meaningful comparison of ${A}_{\mathrm{zz}}(0\ifmmode^\circ\else\textdegree\fi{})$ for the two reactions could be made. The absolute scale of the $^{3}\mathrm{He}(d,p)^{4}\mathrm{He}$ analyzing power was calibrated at four energies using the isospin forbidden $^{16}\mathrm{O}(d,{\ensuremath{\alpha}}_{1})^{14}\mathrm{N}$ reaction. Large differences in ${A}_{\mathrm{zz}}(0\ifmmode^\circ\else\textdegree\fi{})$ for the two reactions were observed for energies both below 1.65 MeV and above 4 MeV. The $^{3}\mathrm{H}(d,n)^{4}\mathrm{He}$ data reported here resolve discrepancies in published data of other authors; the $^{3}\mathrm{He}(d,p)^{4}\mathrm{He}$ results confirm previously reported measurements, except for a small scale shift.NUCLEAR REACTIONS $^{3}\mathrm{He}(\stackrel{\ensuremath{\rightarrow}}{d},p)^{4}\mathrm{He}$, $^{3}\mathrm{H}(\stackrel{\ensuremath{\rightarrow}}{d},n)^{4}\mathrm{He}$, $E=0.24\ensuremath{-}6.75$ MeV; measured ${A}_{\mathrm{zz}}(0\ifmmode^\circ\else\textdegree\fi{})$; calibrated beam polarization by $^{16}\mathrm{O}(\stackrel{\ensuremath{\rightarrow}}{d},{\ensuremath{\alpha}}_{1})^{14}\mathrm{N}$ reaction.

D(d,n)3He Differential Cross Sections from 18 to 26 MeV

Angular distributions of the D(d, n)3He reaction have been measured for incident deuteron energies of 18, 20, 22, 24 and 26 MeV. The data provide no evidence for the proposed broad level in 4He at approximately 30 MeV.

Angular dependence of neutron polarization for theH2(d,n)He3reaction for deuteron energies less than 500 keV

The angular dependence of the polarization of the neutrons from the reaction $^{2}\mathrm{H}(d,n)^{3}\mathrm{He}$ has been determined for 290 keV and 460 keV incident deuterons. These polarization distributions differ in the 30\ifmmode^\circ\else\textdegree\fi{} to 50\ifmmode^\circ\else\textdegree\fi{} lab region from the previous measurement in this energy region and are discussed in relation to both the low energy theory of the reaction and the approach cross-section description.NUCLEAR REACTIONS $^{2}\mathrm{H}(d,n)$, $E=290,460$ keV; measured polarization $P(\ensuremath{\theta})$.

Investigation of charge symmetry violation in the mirror reactions 2H(d, p) 3H and 2H(d, n) 3He

Precision measurements of the angular distributions of the vector and the three tensor analysing powers of the mirror reactions 2H(d, p) 3H and 2H(d, n) 3He are compared betwen 1.5 and 15.5MeV incident deuteron energy. Large and complex differences are observed over the whole energy range. After applying approximate Coulomb corrections, the discrepancies are essentially constant above 4 MeV deuteron energy. Although at present calculations which treat the Coulomb interaction in an exact way cannot be made, there is strong evidence for charge symmetry violation in these mirror reactions.

Study of the energy dependence of the 16O(d, 6Li) 12C reaction

16O(d, 6Li) 12C reaction cross sections have been measured at incident deuteron energies of 80, 65, 60 and 50 MeV. The experimental angular distributions for the ground state transitions have been analyzed by finite range DWBA calculations, employing different values for the potential depths of the 6Li optical potential. Alpha-transfer spectroscopic factors for the 0 + ground state, for the 2 + first excited and for the 4 + state at 14.08 MeV in 12C have been extracted. The variations of these spectroscopic factors are discussed in terms of an energy dependent optical model parametrization.

Spins and parities of low-lying states in 77Kr from the [formula omitted] reaction

The differential cross sections and vector analyzing powers for the 78 Kr( d, t ) 77 Kr reaction leading to low-lying states of 77Kr have been measured at an incident deuteron energy of 15.95 MeV. These data have been compared with distorted-wave Born approximation calculations, as well as with measurements of cross sections and analyzing powers on neighboring nuclei, in order to determine the spins and parities of these states and the spectroscopic factors for the transitions populating them. The ground state of 77Kr, which had been the object of several conflicting spin assignments, has been found to have J π = 5 2 + .