. Author manuscript; available in PMC: 2013 Apr 1.

Published in final edited form as: Appl Radiat Isot. 2011 Dec 29;70(4):743–751. doi: 10.1016/j.apradiso.2011.12.032

Table 2.

Comparison of activities of point radiation sources: reference values and those calculated with the detector model from background subtracted measurements of exposure rate.

Isotope	Reference activity—R (kBq)	d = 0.15 cm			d = 10 cm
Isotope	Reference activity—R (kBq)	Background^a subtracted measurement of exposure rate (μR h⁻¹)	Calculated activity—C (kBq)	Relative error (C–R)/R (%)	Background^b subtracted measurement of exposure rate (μR h⁻¹)	Calculated activity—C (kBq)	Relative error (C–R)/R (%)
²⁴¹Am	108.4	1188	122.4	12.9	44.5	121.2	11.8
⁵⁷Co	41.0	1138	40.6	−1.0	46.5	36.8	−10.2
¹³³Ba	53.7	2138	56.5	5.2	102.5	58.3	8.6
¹³⁹Ce	16.7	508	16.8	0.6	23.5	17.0	1.8
¹³⁷Cs	126.9	1238	122.2	−3.7	63.5	112.3	−11.5
²²⁸Th	35.1	1088	31.0	−11.7	52.5	30.8	−12.3
¹⁵²Eu	45.2	1538	44.2	−2.2	70.5	42.6	−5.8

Background exposure rate was equal to 12 μR h⁻¹.

Background exposure rate was equal to 12.5 μR h⁻¹.