LIFETIME MEASUREMENTS FROM K39(P,GAMMA)CA40 REACTION

Lifetime measurements with a Ge(Li) detector have been made for several excited states of Ca40 by the Doppler-shift attenuation method utilizing the K39 (p,γ)Ca40 reaction. Agreement with results of (p,p′γ) lifetime measurements is found for levels at 3.904, 5.280, and 6.285 MeV. New lifetime results are reported for levels at 5.615 MeV (>0.8 psec), 7.465 MeV (0.010-0.006+0.005 psec), and 7.562 MeV (0.26-0.07+0.14 psec. An upper limit of 1% is set for the branching of the 3.904-MeV (2+) to the 3.354-MeV (0+) levels. Comparison is made with Gerace and Green's predictions that the 5.280-, 3.904-, and 3.354-MeV levels form a rotational band. Calibration of the resonance spectrum with Co56 γ rays has resulted in precise establishment of level energies for Ca40, a better Q value for the reaction of 8.3295±0.0009 MeV, and the association of the lower member of the doublet near 5.615 MeV with the 4- level in this region. New decay modes are established for the levels at 7.113, 7.562, and 7.811 MeV. © 1968 The American Physical Society.