Author/Authors :
M. Paul، نويسنده , , Adrianne C. Feldstein، نويسنده , , I. Ahmad، نويسنده , , D. Berkovits، نويسنده , , C. Bordeanu، نويسنده , , J. Caggiano، نويسنده , , S. Ghelberg، نويسنده , , J. Goerres، نويسنده , , J. Greene، نويسنده , , M. Hass، نويسنده , , A. Heinz، نويسنده , , D. Henderson، نويسنده , , S.K. Hui، نويسنده , , R.V.F. Janssens، نويسنده , , C.L. Jiang، نويسنده , , S. Jiang، نويسنده , , Y. Nirel، نويسنده , , R.C. Pardo، نويسنده , , William T. Pennington، نويسنده , , K.E. Rehm، نويسنده , , et al.، نويسنده ,
Abstract :
Among the many production and destruction nuclear reactions that bear on the net 44Ti yield in the supernova environment, recently highlighted by γ-ray astronomy observations, the α capture on 40Ca stands out in the α-rich freezeout phase conjectured by astrophysical models. We activate a He-gas target with a 40Ca beam and implant recoiling 44Ti nuclei (∼106) in a Cu catcher. The 44Ti atoms chemicallyextracted with a natTi carrier are counted by accelerator mass spectrometry (AMS). The measurement of the 44Ti/Ti ratio, together with the amount of Ti carrier added, determine the number of 44Ti nuclei produced in the activation, independent of chemical yield or transmission efficiency. The resonance strength (7.4±2.5 eV) at Ecm ∼1.1 MeV/n determined for two close-by levels of 44Ti is in excellent agreement with previous prompt-γ measurements. We plan to extend our experiments to the lower energy range.
