Fig. 1. Schematic diagram of single-cell calorimeter (a) and multi-cell or differential calorimeter (b)

Fig. 2. Schematic of single-cell calorimeter components (a) and differential calorimeter components (b)

Fig. 3. Structural diagram of single-cell calorimeters (color online)

Fig. 4. Structural diagram of differential structure calorimeters (color online)

Fig. 5. Schematic of calorimeters with multi-parameter detection(a) CALMOS-2 calorimeter, (b) CARMEN 1P calorimeter, (c) GAMMA MAJOR calorimeter, (d) INTERCAL calorimeter

Fig. 6. Schematic diagram of out-pile transient-state of calibration-operating protocol (a) and calibration system (b)

Fig. 7. Scheme of out-pile steady-state of calibration-operating protocol (a) and calibration system (b)

Fig. 8. Schematic of three calibration methods (a) Calibration coefficient method, (b) Zero rest method, (c) Additional current method