Production and standardization of an on-demand protactinium-233 tracer

Preparation and calibration of a 231Pa reference material

“…The two principal methods for obtaining starting material for a 233 Pa IDMS spike are separation from 237 Np [5,7] and thermal neutron irradiation of 232 Th [7][8][9][10]. The 237 Np nuclide has a half-life of (2.144 ± 0.007) 10 6 a [11], decaying by α particle emission directly to 233 Pa with a half-life of only (26.98 ± 0.02) days [12].…”

“…This calibration method requires a difficult dissolution of a silicate rock material, is fundamentally dependent on a known or precisely measured uranium concentration, and results in a complicated traceability chain for the measurements. Naperstkow et al [10] avoided the use of rock standards and reverse IDMS by employing efficiency traced liquid scintillation counting (CNET 1 ), 4πβ-γ coincidence, and 4πβ-γ anticoincidence radioactivity measurement methods to calibrate a 233 Pa solution with resulting uncertainties between 0.8 and 1% (k = 2). Although this traceable activity-based calibration was performed using sophisticated counting methods that are not routinely used outside of laboratories specializing in radioactivity measurements, an ion chamber can be calibrated for more routine activity-based 233 Pa spike characterization.…”