Beryllium is a light element having an atomin number of 4. Beryllium
is not created during the familiar courses of nuclear reactions in the
stars, but is primariliy created by spallation of heavier nuclei by
cosmic rays. Beryllium is also created during the early cosmic
nucleosynthesis, whose reaction rate is considered to reflect the baryon
contents of the universe. Therefore the measurement of primeaval Beryllium
is a key in understanding the composition of our universe and its fate.