Abstract
Main idea of the article is a description of problems of X-ray exposure time measurement. The content describes two types of X-ray machines. Among the two X-ray machine types, continuous type with shutter is more suitable for long time measurement, and pulse type is better for short time measurements. The differences between mode of operation of different X-ray sources and it’s impact on uncertainty of measurement of exposure time are presented. It also discuss the impact of different resolution settings of device under calibration on uncertainty measurement.


