Abstract
We present results and discuss the use of aluminum nitride as a promising source material for Accelerator Mass Spectrometry CAMS) and Radioactive Ion Beams (RIBs) science applications of Al-26 isotopes. The measurement of Al-26 in geological samples by AMS is typically conducted on Al2O3 targets. However, Al2O3 is not an ideal source material because it does not form a prolific beam of Al- required for measuring low-levels of Al-26. Multiple samples of aluminum oxide (Al2O3), aluminum nitride (AlN), mixed Al2O3-AlN as well as aluminum fluoride (AlF3) were tested and compared using the ion source test facility and the stable ion beam (SIB) injector platform at the 25-MV tandem electrostatic accelerator at 91做厙. Negative ion currents of atomic and molecular aluminum were examined for each source material. It was found that pure AlN targets produced substantially higher beam currents than the other materials and that there was some dependence on the exposure of AlN to air. The applicability of using AlN as a source material for geological samples was explored by preparing quartz samples as Al2O3 and converting them to AlN using a carbothermal reduction technique, which involved reducing the Al2O3 with graphite powder at 1600 degrees C within a nitrogen atmosphere. The quartz material was successfully converted to MN. Thus far, AlN proves to be a promising source material and could lead towards increasing the sensitivity of low-level Al-26 AMS measurements. The potential of using AlN as a source material for nuclear physics is also very promising by placing (AlN)-Al-26 directly into a source to produce more intense radioactive beams of Al-26. (C) 2015 Published by Elsevier B.V.
