The Next Generation of Current Measurement for Ionization Chambers

Published

September 1, 2020

Author(s)

Ryan P. Fitzgerald, Denis E. Bergeron, Dean G. Jarrett, Neil M. Zimmerman, Carine Michotte, Hansjoerg Scherer, Stephen Giblin, Steven Judge

Abstract

Re-entrant ionization chambers (ICs) are essential to radionuclide metrology and nuclear medicine for maintaining standards and measuring half-lives. Metrology-quality systems must be precise and stable to 0.1% over many years, and linear from 10^(-14) A to 10^(-8) A. Thus, labs depend on bespoke current measurement systems and often rely on sealed sources to generate reference currents. To maintain and improve present capabilities, metrologists need to overcome two looming challenges: ageing electronics and decreasing availability of sealed sources. Possible solutions using Ultrastable Low-Noise Current Amplifiers (ULCAs), resistive-feedback electrometers, and (quantum) single-electron pumps are reviewed. Broader discussions of IC design and methodology are discussed. ULCAs show promise and resistive-feedback systems which take advantage of standard resistor calibrations offer an alternative.

Citation

Applied Radiation and Isotopes

Pub Type

Journals

Download Paper

https://doi.org/10.1016/j.apradiso.2020.109216

Local Download

Keywords

Ionization chambers, current measurement, small currents, gamma-ray

Citation

Fitzgerald, R. , Bergeron, D. , Jarrett, D. , Zimmerman, N. , Michotte, C. , Scherer, H. , Giblin, S. and Judge, S. (2020), The Next Generation of Current Measurement for Ionization Chambers, Applied Radiation and Isotopes, [online], https://doi.org/10.1016/j.apradiso.2020.109216, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=927797 (Accessed July 26, 2025)