Table 1.

The detection efficiency of TLCC for a point-like source at the center of FOV under the conditions of the simulation and experiment.

Settings of Gamma Emission Conditions		Nuclide	Representative Energy (keV)	Measured Counts of Incident Gamma-rays	Counts of Effective 2-Events	Proportion of Effective Events (%)
Simulation (N gammas emit within Ω = 0.031 sr at d = 1 m, N is equal to the sum of the emission probability of each energy branch multiplied by the number 107)	N = 13,418,000	133Ba	356	760,871	11,266	1.48
	N = 8,499,000	137Cs	661.7	317,619	10,029	3.16
	N = 19,983,260	60Co	1173.2/1332.5	585,709	13,415	2.29
Experiment (Point-like source with radioactivity A, distance d, and acquisition time t)	A = 0.262 MBq d = 0.25 m t = 3600 s	133Ba	356	376,788	8253	2.19
	A = 1.88 MBq d = 1 m t = 1800 s	137Cs	661.7	628,321	13,186	2.10
	A = 1.92 MBq d = 1 m t = 1800 s	60Co	1173.2/1332.5	1,129,416	20,176	1.79