Calibration of a direct nuclear activation diagnostic which uses boron nitride to measure energetic deuterium ions

A direct nuclear activation diagnostic for the measurement of the kinetic energy of deuterium ions in the energy range of 1-3 MeV has been successfully developed. This diagnostic is based on the fact that the ratio of two different thick-target yields which are generated by the same incident ion species can be a sensitive function of incident ion energy. Targets for this diagnostic are made of alpha-boron nitride (BN) and use the two reactions: B-10(d,n) C-11(beta+) and N-14(d,n) O-15(beta+). The ratio of thick-target yields depends only on the deuterium ion energy and is independent of ion fluence and detector efficiency. The calibrated diagnostic was then fielded to measure the voltage in a plasma opening switch (POS). Electrical measurements of the POS voltage and the voltage inferred from the BN nuclear activation diagnostic were in good agreement. (C) 1999 American Institute of Physics. [S0034-6748(99)59501-4].