An adiabatic calorimeter for calibrating capsule type thermometers (CSPRTs) in the range 54 K to 273 K

National Institute of Standards, Tersa St., El Haram, 12211 Giza, Egypt

^⋆ Correspondence: gamal70@yahoo.com

Received: 5 May 2012
Accepted: 10 June 2012

Abstract

A new comparison system has been constructed for the calibration of capsule-type standard platinum resistance thermometers (CSPRTs) below 273.16 K at the National Institute of Standards (NIS-Egypt). The system can compare two CSPRTs at once. A gold plated comparison block, in which CSPRTs are mounted for calibration, is made from oxygen-free high-conductivity copper. A description of the system and the comparison block along with the comparison method is given. The standard uncertainty related to the temperature control of the system is estimated to be 0.04 mK. The calibrated values for CSPRTs and obtained using the comparison system are in good agreement with those obtained by the direct realization of the low temperature fixed points of the ITS-90 within the combined standard uncertainty.