Z. Ayer

Determination of the asymptotic D- to S-state ratio for He3 via (d,He3) reactions

Angular distributions of the tensor analyzing powers {ital A}{sub {ital yy}} and {ital A}{sub {ital zz}} have been measured for the ground-state transition in the {sup 93}Nb({ital {rvec d}},{sup 3}He){sup 92}Zr reaction at {ital E}{sub {ital d}}=12 MeV, and of {ital A}{sub {ital zz}} for the ground-state transitions in {sup 63}Cu({ital {rvec d}},{sup 3}He){sup 62}Ni at {ital E}{sub {ital d}}=8 MeV and {sup 89}Y({ital {rvec d}},{sup 3}He){sup 88}Sr at {ital E}{sub {ital d}}=10.5 MeV. The data are compared with predictions of full finite-range distorted-wave Born approximation (DWBA) calculations from which the asymptotic {ital D}- to {ital S}-state ratio, {eta}, for {sup 3}He is extracted to be {minus}0.0386{plus_minus}0.0045{plus_minus}0.0012. The difficulties with a choice of deuteron tensor optical potentials used in the DWBA calculations are discussed.

Determination of the asymptotic D- to S-state ratio of the triton from sub-coulomb (d→,t) reactions

Angular distributions of the tensor analyzing power [ital A][sub [ital z][ital z]] have been measured for ground state transitions in [sup 119]Sn([ital [rvec d]],[ital t])[sup 118]Sn and [sup 149]Sm([ital [rvec d]],[ital t])[sup 148]Sm and the first excited state (0.263 MeV) in[sup 206]Pb([ital [rvec d]],[ital t])[sup 205]Pb for deuteron energies well below the Coulomb barrier. Exact, finite-range distorted-wave Born approximation analyses of these data have been made to establish the asymptotic [ital D]- to [ital S]-state ratio for the triton, [eta][sub [ital t]]. These calculations include a deuteron-nucleus tensor potential determined from the folding model and a long-range tensor potential arising from the Coulomb interaction. Previously obtained [ital A][sub [ital z][ital z]]([theta]) data for the ground state transitions in [sup 95]Mo([ital [rvec d]],[ital t])[sup 94]Mo, [sup 119]Sn([ital [rvec d]],[ital t])[sup 118]Sn, and [sup 149]Sm([ital [rvec d]],[ital t])[sup 148]Sm at different sub-Coulomb energies have been reanalyzed. Also a careful investigation of possible uncertainties in the value of [eta][sub [ital t]] is presented. A best fit to the data gives [eta][sub [ital t]]=[minus]0.0411[plus minus]0.0013[plus minus]0.0012, somewhat lower than previous experimental determinations.

Ion implanted 3He targets for very low energy experiments

Abstract Helium-3 was implanted into tantalum and aluminum foils at implant energies ranging from 7 to 20 keV and with ion fluences exceeding 10 19 ions/cm 2 for the purpose of producing targets for nuclear reaction experiments. The effects of implant energy, fluence, and temperature on target thickness were studied. The foils were bombarded with deuterons to initiate the 3 He(d,p) 4 He reaction near the 430 keV resonance to determine target thicknesses, thickness lifetimes, and to study the properties of this reaction as a polarization analyzer. Results indicate that these targets can be used in an efficient low-energy polarization analyzer.

A deuteron tensor polarimeter for low-energy experiments

A deuteron tensor polarimeter utilizing the 3He(d,p)4He reaction has been calibrated at energies between 113 and 323 keV using implanted 3He targets. It provides an efficient determination of polarization at deuteron energies between 100 and 700 keV due to the presence of the 32+ resonance at Ed = 430 keV. In an energy range around the resonance the tensor analyzing power Ayy = 0.5 at all angles and Azz is −0.85 at a mean angle of 17.5°.

The use of the 3He(d↘,p)4He reaction for polarimetry at low energies

Angular distributions of tensor analyzing powers Ayy and Azz have been measured in 3He(d,p)4He reaction in the 130 to 322 keV energy range. The reaction proves to be very efficient and easy to use to determine polarization of deuteron beams.

Determination of the asymptotic D‐ to S‐state ratio for the triton and 3He via (d↘,t) and (d↘,3He) reactions

Angular distributions of tensor analyzing powers (TAPs) have been measured in sub‐Coulomb (d,t) reactions and in (d,3He) reactions on several targets and at several energies. The data are compared with predictions of full finite‐range distorted‐wave Born approximation (DWBA) calculations from which the asymptotic D‐ to S‐state ratios, ηt and η(3He) for the triton and 3He, respectively, are extracted. A best fit to the (d,t) data yields ηt=−0.0411±0.0013±0.0012, while the best‐fit value of η(3He) extracted from the (d,3He) data is −0.0380±0.0026±0.0011.

Determination of the asymptotic {ital D}- to {ital S}-state ratio for {sup 3}He via ({ital {rvec d}},{sup 3}He) reactions

Angular distributions of the tensor analyzing powers {ital A}{sub {ital yy}} and {ital A}{sub {ital zz}} have been measured for the ground-state transition in the {sup 93}Nb({ital {rvec d}},{sup 3}He){sup 92}Zr reaction at {ital E}{sub {ital d}}=12 MeV, and of {ital A}{sub {ital zz}} for the ground-state transitions in {sup 63}Cu({ital {rvec d}},{sup 3}He){sup 62}Ni at {ital E}{sub {ital d}}=8 MeV and {sup 89}Y({ital {rvec d}},{sup 3}He){sup 88}Sr at {ital E}{sub {ital d}}=10.5 MeV. The data are compared with predictions of full finite-range distorted-wave Born approximation (DWBA) calculations from which the asymptotic {ital D}- to {ital S}-state ratio, {eta}, for {sup 3}He is extracted to be {minus}0.0386{plus_minus}0.0045{plus_minus}0.0012. The difficulties with a choice of deuteron tensor optical potentials used in the DWBA calculations are discussed.

Determination of the asymptotic D- to S-state ratio for He-3 via (d -->, He-3) reactions

Angular distributions of the tensor analyzing powers {ital A}{sub {ital yy}} and {ital A}{sub {ital zz}} have been measured for the ground-state transition in the {sup 93}Nb({ital {rvec d}},{sup 3}He){sup 92}Zr reaction at {ital E}{sub {ital d}}=12 MeV, and of {ital A}{sub {ital zz}} for the ground-state transitions in {sup 63}Cu({ital {rvec d}},{sup 3}He){sup 62}Ni at {ital E}{sub {ital d}}=8 MeV and {sup 89}Y({ital {rvec d}},{sup 3}He){sup 88}Sr at {ital E}{sub {ital d}}=10.5 MeV. The data are compared with predictions of full finite-range distorted-wave Born approximation (DWBA) calculations from which the asymptotic {ital D}- to {ital S}-state ratio, {eta}, for {sup 3}He is extracted to be {minus}0.0386{plus_minus}0.0045{plus_minus}0.0012. The difficulties with a choice of deuteron tensor optical potentials used in the DWBA calculations are discussed.

Determination of the asymptoticD- toS-state ratio forHe3via (d→, He3) reactions

Angular distributions of the tensor analyzing powers {ital A}{sub {ital yy}} and {ital A}{sub {ital zz}} have been measured for the ground-state transition in the {sup 93}Nb({ital {rvec d}},{sup 3}He){sup 92}Zr reaction at {ital E}{sub {ital d}}=12 MeV, and of {ital A}{sub {ital zz}} for the ground-state transitions in {sup 63}Cu({ital {rvec d}},{sup 3}He){sup 62}Ni at {ital E}{sub {ital d}}=8 MeV and {sup 89}Y({ital {rvec d}},{sup 3}He){sup 88}Sr at {ital E}{sub {ital d}}=10.5 MeV. The data are compared with predictions of full finite-range distorted-wave Born approximation (DWBA) calculations from which the asymptotic {ital D}- to {ital S}-state ratio, {eta}, for {sup 3}He is extracted to be {minus}0.0386{plus_minus}0.0045{plus_minus}0.0012. The difficulties with a choice of deuteron tensor optical potentials used in the DWBA calculations are discussed.

Determination of the asymptotic [ital D]- to [ital S]-state ratio of the triton from sub-Coulomb ([ital [rvec d]],[ital t]) reactions

Angular distributions of the tensor analyzing power [ital A][sub [ital z][ital z]] have been measured for ground state transitions in [sup 119]Sn([ital [rvec d]],[ital t])[sup 118]Sn and [sup 149]Sm([ital [rvec d]],[ital t])[sup 148]Sm and the first excited state (0.263 MeV) in[sup 206]Pb([ital [rvec d]],[ital t])[sup 205]Pb for deuteron energies well below the Coulomb barrier. Exact, finite-range distorted-wave Born approximation analyses of these data have been made to establish the asymptotic [ital D]- to [ital S]-state ratio for the triton, [eta][sub [ital t]]. These calculations include a deuteron-nucleus tensor potential determined from the folding model and a long-range tensor potential arising from the Coulomb interaction. Previously obtained [ital A][sub [ital z][ital z]]([theta]) data for the ground state transitions in [sup 95]Mo([ital [rvec d]],[ital t])[sup 94]Mo, [sup 119]Sn([ital [rvec d]],[ital t])[sup 118]Sn, and [sup 149]Sm([ital [rvec d]],[ital t])[sup 148]Sm at different sub-Coulomb energies have been reanalyzed. Also a careful investigation of possible uncertainties in the value of [eta][sub [ital t]] is presented. A best fit to the data gives [eta][sub [ital t]]=[minus]0.0411[plus minus]0.0013[plus minus]0.0012, somewhat lower than previous experimental determinations.