Automated Multi-Sample Ionization Chamber for Radioactivity Standards

NIST radioactivity standards for gamma-ray emitting radionuclei are presently maintained as calibration factors for a single, manually operated, ionization chamber instrument

A new automated ionization chamber has been developed at NIST to measure up to 100 samples with programmable sample queuing, sample handling and measurement parameters while maintaining the high precision and reproducibility of the manual instrument. Routine use of this new instrument will reduce radiation exposure to operators, expedite the standards-transfer process and improve quality assurance. Over the past 2 years, NIST has established calibration factors for ^99mTc, ²⁰¹Tl, ²⁰⁰Tl, ²⁰²Tl, ¹³¹I, ⁵⁴Mn, ¹¹¹In, ⁶⁷Ga, ¹⁷⁷Lu, ⁶⁰Co, ⁵⁷Co, ⁵⁹Fe and ¹³³Xe, using primary standardizations whenever possible. Key safety and usability upgrades have made the system ready for routine use and a 2010 peer-reviewed publication has demonstrated the linearity and reproducibility of the system.


Image Description: NIST automated ionization chamber in action. Specially-designed sample-holders and positioning system ensure high degree of reproducibility.