Analyse der elastischen Streuung von Deuteronen an 12C nach dem optischen modell im energiebereich von 10.6 MeV bis 13.9 MeV

Baldeweg, F.; Bredel, V.; Guratzsch, H.; Klabes, R.; Kühn, B.; Stiller, G. P.

doi:10.1016/0029-5582(66)90373-7

Cited by 13 publications

(1 citation statement)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…According to the discussion of the preceding section, this would lead to errors in the deduced values of p zz , increasing with the irradiation time. The necessity of corrections due to an increase of δ in d− 12 C reactions ("carbon buildup") was mentioned earlier [33], [34], and [35], whereas no significant change was found in [36]. As result of a systematic study [37], an increase of δ is to be expected due to deposition of carbon atoms on the target surface confined to the irradiated area with a characteristic deposition rate of 1 • 10 14 C atoms cm −2 µCb −1 .…”

Section: B Time Dependence Of the Areal Target Densitiesmentioning

confidence: 91%

Rapid fluctuation of the tensor polarization of deuteron beams behind carbon foils and their relation to the resonances in the isospin-breaking $^{12}{\rm C}(d,α_{2})^{10}{\rm B}^{*}$ reaction

Seyfarth,

Rouba,

Baryshevsky

et al. 2017

Preprint

View full text Add to dashboard Cite

Rapid fluctuations are observed in the tensor-polarization pzz of deuteron beams forwardtransmitted through graphite targets. Unpolarized 9.50 to 18.60 MeV beams from the Köln tandem accelerator were utilized, and the polarization behind seven 36 to 188 mg/cm 2 targets was measured with a polarimeter based on the 3 He( d, p) 4 He reaction. Due to the chosen relation between the areal target densities and the initial beam energies Ein, the seven sets of pzz(Ein) can be combined in a common plot as a function of Ein. This allows one to understand pzz, measured behind the 188 mg/cm 2 target at Ein=18.6 MeV, as resulting from the sequence of differential polarization production ∆pzz(E)/∆E during energy degradation in the target from E=18.60 to 9.50 MeV. The rapid fluctuations of ∆pzz(E)/∆Epzz are described by 51 Gaussian-distributed cross-sections removing deuterons either in the m = 0 or in the m = ±1 state from the beam. The 51 fitted central energies E0 with a single exception agree with the energies of the narrow peaks in the excitation functions of the weak, isospin-breaking 12 C(d, α2) 10 B * (1.74 MeV, J π = 0 + , T = 1) reaction with population of the second excited 10 B state via intermediate excited 14 N states. Angular momentum and parity conservation confines their spin values to J = l, the orbital angular momentum in the entrance state. Formation of J = l ± 1 states with other decay channels would be possible. According to the fit result, formation of J = l excited 14 N states dominates in the removal of deuterons from the beam. The coarse energy dependence of the present fluctuations corresponds to the excitation of the 14 N giant electric dipole resonance, split into regions of ∆pzz(E)/∆E >0 and <0. Strong evidence is found that removal of deuterons in the m = 0 (m = ±1) state from the beam leads to the formation of 14 N states of established positive (negative) parity. As an application, the removal cross-section functions allow to calculate pzz achievable with carbon targets for initial beam energies Ein between 18.60 and 9.50 MeV and Eout given by the areal target density. Carbon layers in a sandwich technique would enable pzz between -0.4 and +0.3.

show abstract