The nuclide 44Ti (T1/2 - 59.2 yr) has recently become an important asset to nuclear astrophysics through the measurement of its cosmic radioactivity, yielding significant information on fresh 44Ti nucleosynthesis in supernovae. We propose to use AMS to determine the production rate of 44Ti by the main channel believed to be responsible for 44Ti astrophysical production, namely 40Ca(α, γ). A preliminary experiment conducted at the Koffler 14UD Pelletron accelerator demonstrates a sensitivity of 1 × 10-14 for the 44Ti/Ti ratio. The AMS detection was performed using 44Ti- ions sputtered from a TiO2 sample, reducing considerably the 44Ca isobaric interference. The present limit corresponds effectively to 44Ti production with resonance strength in the range 10-100 meV for a one-day 40Ca(αi, γ) activation. Several such resonances are known to be responsible for 44Ti production in the astrophysical temperature range and should be amenable to experiment with the proposed method.
|Original language||English (US)|
|Number of pages||5|
|Journal||Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms|
|State||Published - 2000|
Bibliographical noteFunding Information:
We should like to gratefully acknowledge the advice and help of R. Herber and A. Kaufman in the chemical sample preparation. This work was supported in part by the US–Israel Binational Science Foundation.