BS EN IEC 61788-23:2021

What is IEC 61788-23 about?  

BS EN IEC 61788-22 is a series of International Standards on superconductor electronic devices. 

BS EN IEC 61788-23 is the 23rd part of the multi-series that addresses a test method for the determination of the residual resistance ratio (RRR) of cavity-grade niobium. This method is intended for high-purity niobium grades. 

The test method mentioned in BS EN IEC 61788-23 is valid for specimens with rectangular or round cross-sections, a cross-sectional area greater than 1 mm2 but less than 20 mm2, and a length not less than 10 nor more than 25 times the width or diameter. 

Who is BS EN IEC 61788-23 for?  

BS EN IEC 61788-23 on superconductivity is relevant to: 

• Manufacturers of superconducting wire 
• Scientific and technological services 
• Manufacturers of applications like magnetic resonance imaging (MRI) 
• Mineral exploration 
• Earthquake prediction  
• Geothermal applications 

Why should you use BS EN IEC 61788-23?  

Superconductivity is the ability of certain materials to conduct electric current with practically zero resistance. In this regard, high-purity niobium is the chief material used to make superconducting radio-frequency cavities. Meanwhile, RRR is the ratio of resistance at room temperature to the resistance just above the superconducting transition. 

This document describes a test method to determine the residual resistance value by using a plot of the resistance to temperature as the test specimen is gradually warmed through the superconducting transition in the absence of an applied magnetic field. This results in a determination of the residual resistance at just above superconducting transition, ~10 K, from which RRR is subsequently determined. 

BS EN IEC 61788-23 provides guidance for sample dimensions and electrical connections.  

As a result, accurate measurement of RRR of niobium samples can assure that critical material-purity specifications are met in the construction of superconducting radio-frequency cavities. Apart from this, BS EN IEC 61788-23 also provides you with indications on low temperature thermal conductivity of the niobium. 

What’s changed since the last update? 

BS EN IEC 61788-23:2021 replaces the first edition published in 2018. BS EN IEC 61788-23:2021 includes the following significant technical changes with respect to the previous edition: 

• The scope of this standard was modified to restrict the range of residual resistance ratio to that encountered by providers of material for superconducting radiofrequency cavities 
• The references to technical material were updated and corrected