AL-26(N,P(1)) AND (N,ALPHA(0)) CROSS-SECTIONS FROM THERMAL-ENERGY TO 70 KEV AND THE NUCLEOSYNTHESIS OF AL-26

We have measured the Al-26(n,alpha(0))Mg-23 and Al-26(n,p(t))Mg-26 cr oss sections from thermal energy to approximately 10 keV and 70 keV, r espectively. These reactions are thought to be the major mechanisms fo r the destruction of Al-26 in many nucleosynthesis environments; hence , an accurate determination of their rates is important far understand ing the observations of gamma rays from ''live'' Al-26 in our galaxy a nd of ''extinct'' Al-26 in meteorites. The astrophysical rate for the Al-26(n,alpha(0))Mg-23 reaction determined from our measurements is in good agreement with the rate determined via inverse measurements. On the other hand, the rate we determined for the Al-26(n,p(t))Mg-26 rea ction is significantly larger than previously reported. In addition, w e were able to determine this rate in the temperature range below 0.2 GK which was not covered by previous measurements. This lower temperat ure range may be important for understanding the production of Al-26 i n Red Giant stars. Both of our rates are significantly different than the rates used in most nucleosynthesis calculations, We discuss the im pact of our measurements on the nucleosynthesis of Al-26.