Measurement technique of concentration of positive and negative air ions

Measurement technique of concentration of positive and negative air ions

The technique is developed in KSTU of A.N. Tupolev on faculty "Standardizations, certifications and technological management" according to the established requirements in accordance with GOST Р 8.563-96. 

Techniques of performance of measurement. 
The technique is intended for measurements performance of  concentration of the positive and negative air ions contained in 1cmof air under normal conditions, with the help of the air ion counter "Sapphire-3К" (State register № 18295-99). 
The technique provides performance of measurements for concentration of air ions in a range from 2*102 up to 2*106 cm with a relative error not more than 0,4 +0,01*[(nk/nx)-1], where nis final value of a sub range limit in  measurements of the counter; nx - indications of the counter. 

The counter has four sub ranges:

  • 1st  sub range from 2*102  to 2*103  cm-3
  • 2nd sub range from 2*103  to 2*104  cm-3
  • 3rd sub range from 2*104  to 2*105  cm-3 
  • 4th  sub range from 2*105  to 2,5*106  cm-3 

The technique needs the reference counter maintained under normal conditions according to GOST 14763-78. The technique is based on application of GOST 8.207-76 regulating direct measurements with repeated independent measurements. When doing statistical processing of the group of observations results the following operations are carried out:

  • - Choose number of results of supervision (indications of the counter) n, then measurements (n> 50, 50> n> 15, n <15) will be made; 
  • - Take n readings from the indicator board of the counter; 
  • - Check the hypothesis about normal distribution of observations; 
  • - Exclude rough observation errors according to the instructions given in GOST 11.002-73; 
  • - Calculate the result of measurement using  the formula

    Where  - are observation results without rough errors.
  • Calculate the measurement result as below
  • Calculate an estimation of the confidence bound for the mean-square error of measurement results, using the formula

    Where   - is a Student's coefficient depending on chosen confidential probability P and number of measurement results;
  • Adjust the measurement results in accordance with GOST 8.011-72.
  • If the confidential error is symmetric, then the measurement results are represented in the form

    When P=: %.

The author of the article - Aydar Tuktagulov (Sapphire Company