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The nuclide 44 Ti is predicted to be produced in significant quantities in corecollapse supernovae, and indeed it has been observed in the supernova remnant Cassiopeia-A by space-based γ -ray telescopes. The main production of 44 Ti takes place in the α-rich freeze-out phase deep inside the supernova.The key reactions governing the 44 Ti abundance have been identified in an earlier sensitivity study. Using the recoil mass spectrometer DRAGON at the TRIUMF-ISAC facility in Vancouver, Canada, we measured the main production reaction 40 Ca(α,γ ) 44 Ti, resulting in an increased reaction rate compared to the rate derived from previous prompt γ -ray studies, which is commonly used in supernova models. The uncertainty of the 44 Ti production is now dominated by the rate of reactions with short-lived nuclides around 44 Ti, namely 45 V(p,γ ) 46 Cr, 44 Ti(α,p) 47 V and 44 Ti(α,γ ) 48 Cr. The sensitivity of these reactions on the 44 Ti production has been revisited.

The short-lived radionuclide 44 Ti, which has been observed in space by γ-ray astronomy, is believed to be produced in supernovae during the α-rich freeze-out by α capture on 40 Ca. This reaction has been studied in inverse kinematics using the recoil mass spectrometer DRAGON at the ISAC facility at TRIUMF in Vancouver, Canada. A large energy range was covered corresponding to the temperature range of T 9 ¡ 1 ¢ 2£ 8 for freeze-out conditions. A preliminary analysis shows additional contribution to the total 44 Ti yield between the resonances measured by prompt γ-ray studies.