OMPI and Social Event: Jaswinder Taank and Malcolm McEwen

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Thursday, September 17, 2015

Time: 3:30-5:00 pm - Refreshments start at 3:15 pm.

Location: Carleton University, Herzberg Building, Room HP4351


1. "Examining the influence of humidity on Farmer chamber performance"

By Jaswinder Taank - McMaster University and National Research Council Canada

Abstract: The average energy required to produce an ion pair in an ion chamber (W) is mostly dependent on the gas, the temperature/pressure of the gas, and the type/energy of the radiation. The humidity of the gas also plays a role, albeit a much smaller one. Its influence appears to be flat for typical room humidities and therefore, it often gets ignored in most scientific labs. However, its influence is much more pronounced near relative humidities of 0 and 100% . ICRU 31, the most comprehensive document on the topic, reports an influence of up to ± 0.3%, but it relies on old data generated from the 60s and 70s. Obtaining a more accurate understanding of this behaviour is important for standards labs in particular, because we require uncertainties of about the same order. In this project, we explore the influence of humidity on various farmer chambers using a weak Sr-90 beta source. We also show our most recent measurements from a Co-60 gamma source.

2. World-Wide Radiation Metrology: The BIPM, the CIPM MRA, SIM and NRC

By Malcolm McEwen - National Research Council Canada

Abstract:  Since the Metre Convention was signed in 1875 there has been steady progress to ensure the consistency of measurements from one country to another. The Bureau International des Poids et Mesures (BIPM) co-ordinates comparison exercises that demonstrate the equivalency of measurement standards from one national laboratory to another with the aim of simplifying international commerce and eliminating cross-border regulatory barriers.
This presentation will describe how the international realization of the SI is managed under the Mutual Recognition Arrangement of the CIPM and show how NRC, as Canada's National Measurement Institute, plays a major role in world-wide radiation metrology. In addition to the explanation of the many acronyms in this field, the presentation will present the results of recent international comparisons of Canadian measurement standards.

Social event details

For the first OMPI social event of the season, we are going to head over to Maclarens (301 Elgin Street) to play some pool. It is a short drive from Carleton University, and we will try to arrange rides for those who need it. If you are interested in participating or making suggestions regarding OMPI socials in the future, please fill out this short form ( Your RSVP via the form would be greatly appreciated.