Polarization in 3He + 4He elastic scattering

Hardy, D.M.; Spiger, R. J.; Baker, Stephen; Chen, Y. S.; Tombrello, T. A.

doi:10.1016/0370-2693(70)90193-0

Cited by 19 publications

(6 citation statements)

References 4 publications

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“…In Fig. 1 we have compared the s-wave phase shifts as calculated with the various nucleon-nucleon interactions with the data of experimental phase shifts analysis of [20][21][22]. The MHN force as well as the MWT and WT forces reproduce the s-wave data in the low energy regime E< 6 MeV rather well; the Volkov V2 interaction underestimates the experimental phase shifts at these energies.…”

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confidence: 83%

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On discrepancies within the experimental and theoretical low energy3H(?, ?)7Li cross sections

Altmeyer

Kolbe

Warmann

et al. 1988

Z. Physik A - Atomic Nuclei

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The two presently available measurements of the low-energy 3H(a, ~)TLi reaction differ from each other by roughly 30% in total magnitude as well as in their determination of the branching ratios for the transition into the two final 7Li bound states. Studying the 3H(e, 7)7Li reaction in the framework of the microscopic Resonating Group Method we were able to reproduce both experimental total cross sections using different effective nucleon-nucleon interactions. However, none of the effective forces yields branching ratios compatible with the data measured by the Toronto-M/inster-collaboration. PACS: 25.55. -e; 25.70.Jj; 21.60.GxThe 3H(e, 7)7Li reaction is a main source for the 7Li production during the big bang nucleosynthesis [1]. Measurements of this reaction rate in the energy range E= 150-600 keV performed by Griffith et al.[2] are consistent with the assumption of an energy independent astrophysical S-factor for the 3H(c~, 7)7Li reaction at stellar energies with a value of S(0)=0.064keV-b [3]. This energy-independent S(E)-factor has been adopted in standard hot big bang model studies [4,5].Recently several microscopic calculations of the 3H(e, 7)VLi reaction at low energies (E < 1 MeV) have been performed in the framework of the Resonating Group Method [6][7][8] or on the basis of a microscopic potential model [9]. While these studies reproduced the experimental data of [2], they do not support the assumption of an energy-independent 3H(e, 7)7Li S-factor at low energies. In agreement with each other these calculations predict the S-factor to increase noticeably with decreasing energy resulting in S(0)~0.10keV.b [6][7][8][9]. Consequently the microscopic studies recommend a higher thermally averaged 3H(c~, 7)7Li reaction rate at astrophysically important temperatures T< 109K than the rate given by Fowler et al. [-3] resulting in a production of 7Li during the big bang which is noticeably higher than currently believed.Motivated by the theoretical predictions a Mfinster-Toronto collaboration [10] has very recently measured the 3H(~, y)VLi cross sections in the energy range E = 80-500 keV. In fact the new experimental data show the predicted increase of the S-factor towards E =0, however, they exceed the data of [-2] by roughly 30% and are also noticeably larger than the microscopically calculated cross sections [6][7][8][9]. An extrapolation of the new experimental data resulted in S (0) ~ 0.14 + 0.02 keV. b [ 10]. Without knowledge of the data of [10] Kajino investigated the dependence of the microscopically calculated 3H(c~, 7)7Li cross sections and those of its analogue reaction 3He(e, 7)TBe on the effective nucleon-nucleon interaction used in these studies [11]. As a main result he observed that the various calculations predict different energy dependences of the Sfactor in the astrophysically important energy regime. In close relation to the study of Kajino [11] we will show in the following that the experimental data of [10] are compatible with the results of the microscopic calculations if other force...

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confidence: 83%

“…Thus we have evaluated the reaction cross sections into the two bound states of 7Li and 7Be, respectively, [18][19][20] with the theoretical results calculated using the MWT interaction restricting our calculation to E 1 capture from the s-and d-wave scattering states only. The theoretical background is outlined in [6][7][8]11].…”

mentioning

confidence: 99%

On discrepancies within the experimental and theoretical low energy3H(?, ?)7Li cross sections

Altmeyer

Kolbe

Warmann

et al. 1988

Z. Physik A - Atomic Nuclei

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“…III. 3 He -4 He AND 3 H -4 He CLUSTER POTENTIALS At incident energies E lab ( 3 He) ≈ 3 − 10 MeV differential cross sections for the elastic 3 He - 4 He scattering are well known [32,33,34,35,36]. In order to obtain cross section data at very low energies we have measured these scattering processes at 20 energies in the range from 1 to 3.3 MeV using the windowless, differential pumped and recirculating gas target system RHINOCEROS installed at the Stuttgart Dynamitron accelerator [37].…”

Section: Direct Capture Model and Folding Proceduresmentioning

confidence: 99%

“…1. The results of different phase-shift analyses [33,35,36] for projectile energies E lab ( 3 He) > 3 MeV are presented in Fig. 2.…”

Section: Direct Capture Model and Folding Proceduresmentioning

confidence: 99%

Alpha scattering and capture reactions in theA=7 system at low energies

et al. 1993

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Differential cross sections for 3 He-α scattering were measured in the energy range up to 3 MeV. These data together with other available experimental results for 3 He +α and 3 H +α scattering were analyzed in the framework of the optical model using double-folded potentials. The optical potentials obtained were used to calculate the astrophysical S-factors of the capture reactions 3 He(α, γ) 7 Be and 3 H(α, γ) 7 Li, and the branching ratios for the transitions into the two final 7 Be and 7 Li bound states, respectively. For 3 He(α, γ) 7 Be excellent agreement between calculated and experimental data is obtained. For 3 H(α, γ) 7 Li a S(0) value has been found which is a factor of about 1.5 larger than the adopted value. For both capture reactions a similar branching ratio of R = σ(γ 1 )/σ(γ 0 ) ≈ 0.43 has been obtained.

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“…A concept low-energy polarimeter design is shown in Figure 5. The analyzing power for elastic scattering of polarized 3 He on unpolarized 4 He is ideally A N = 1 at a beam energy of ∼5.3 MeV and θ CM ≈ 91 • [20,21]. For the 6 MeV polarized 3 He ++ beam emitted from the EBIS linac, there is a local maximum at A N > 0.9 and θ CM ≈ 96 • where the polarization can be determined by measuring the spin correlated asymmetry from scattered 3 He and 4 He.…”

Section: Low-energy 3 He ++ Beam Polarimetrymentioning

confidence: 99%

Polarized 3He++ Ion Source for RHIC and an EIC

Musgrave¹,

Milner²,

Атоян³

et al. 2018

Proceedings of XVII International Workshop on Polarized Sources, Targets &Amp; Polarimetry — PoS(PSTP2017)

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The capability of accelerating a polarized 3 He ion beam in RHIC would demonstrate an effective polarized neutron beam for the study of new high-energy QCD studies of nucleon structure. This development would be particularly beneficial for the future plans of an Electron Ion Collider (EIC), which could use a polarized 3 He ion beam to probe the spin structure of the neutron. The proposed polarized 3 He ion source is based on the Electron Beam Ion Source (EBIS) currently in operation at Brookhaven National Laboratory (BNL). 3 He gas would be polarized within the 5 T field of the EBIS solenoid via Metastability Exchange Optical Pumping (MEOP) and then pulsed into the EBIS vacuum and drift tube system where the 3 He will be ionized by the 10 Amp electron beam. The goal of the polarized 3 He ion source is to achieve 2.5 × 10 11 3 He ++ /pulse at 70% polarization. An upgrade of the EBIS is currently underway at BNL. The EBIS capability to produce polarized 3 He ++ is being developed through a collaboration between BNL and MIT.

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Polarization in 3He + 4He elastic scattering

Cited by 19 publications

References 4 publications

On discrepancies within the experimental and theoretical low energy3H(?, ?)7Li cross sections

On discrepancies within the experimental and theoretical low energy3H(?, ?)7Li cross sections

Alpha scattering and capture reactions in theA=7 system at low energies

Polarized 3He++ Ion Source for RHIC and an EIC

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