Differential cross sections of the reaction /sup 4/He(t,n)/sup 6/Li between 8. 5 and 16. 5 MeV and the n-/sup 6/Li cross-section standard

Abstract

Differential cross sections of the reaction 4 He(t,n) 6 Li, including some data of the first and second excited states of 6 Li, were measured and compared with an R-matrix analysis of previous data in the 7 Li system. Excellent agreement is observed for the angular distribution at the 0.24-MeV resonance of n-6 Li, and the shape of the angular distribution for 4 Hs(t,n,) 6 Li at 12.9 MeV is predicted qualitatively by the R-matrix analysis. However, for neutron energies greater than 0.5 MeV for 6 Li(n,t)*He the zero-degree excitation function is consistently lower (about 30%) in the R-matrix analysis.

Differential cross sections of /sup 3/H(p,n)/sup 3/He and of /sup 6/Li(n,t)/sup 4/He by using triton beams between 5. 95 and 19. 15 MeV and a reevaluation of the p-T neutron production cross sections up to 12 MeV

“…The main contribution for an R-matrix analysis of 7 Li lies in the data involving the first excited state of 6 Li. Table III gives previously unpublished relative angular distributions of 3 H(p,n) 3 He at 2.22 and 3.00 MeV which were measured several years ago. The scale of these data as shown in the table has been obtained by the present evaluation.…”

“…These data wera taken together with already published t- 4 He data 3 ) using the identical cross section references resulting in a scale error of 2.8%. Table V lists the 1 H(t,n) 3 He cross sections which were measured in the present experiment together with the t- 4 He Qcta of Section III. B.…”

“…The previous data 3 are corrected in this paper for a 0.1% impurity of hydrogen in the helium gas. Because of the huge H(t,n) He cross sections this small impurity results in corrections of up to 10% in those cases when the neutron lines of the two reactions overlapped.…”

“…By exchanging the projectile and the target in the 3 H(p,n) 3 He reaction back angle cross sections can be measured at forward angles of the reaction 1 H(t,n) 3 He. Similarly cross sections of the cross section standard 6 Li(n,t) 4 He can be measured by the time-reversed reaction 4 He(t,n) 6 Li.…”

“…Whereas the 4 He(t,n x ) 6 Li data were measured to widen the data base of the R-Matrix analysis of the 7 Li system 2 ) the 1 H(t,n) 3 He data were used to improve the evaluation of the differential neutror. production cross sections of the 3 H(p,n) 3 He reaction.…”