Determination of boron in materials by cold neutron prompt gamma-ray activation analysis.
An instrument for cold neutron prompt gamma-ray activation analysis (PGAA), located at the NIST Center for Neutron Research (NCNR), has proven useful for the measurement of boron in a variety of materials. Neutrons, moderated by passage through liquid hydrogen at 20 K, pass through a (58)Ni coated guide to the PGAA station in the cold neutron guide hall of the NCNR. The thermal equivalent neutron fluence rate at the sample position is 9 x 10(8) cm(-2) s(-1). Prompt gamma rays are measured by a cadmium- and lead-shielded high-purity germanium detector. The instrument has been used to measure boron mass fractions in minerals, in NIST SRM 2175 (Refractory Alloy MP-35-N) for certification of boron, and most recently in semiconductor-grade silicon. The limit of detection for boron in many materials is <10 ng g(-1).
Paul
Rick L
RL
Analytical Chemistry Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
D001895:Boron / Q000032:analysis*; D009502:Neutrons; D013051:Spectrometry, Gamma / Q000295:instrumentation / Q000379:methods
D001895:Boron