TP1 (ceramic) = 20.0°C (measured)
TP2 (window) = 27.0°C (measured)
TP3 (window) = 29.0°C (measured)
QINCIDENT = 20.0W (measured)
QELECTRICAL = 9.5W
RMAX_ARRAY-TO-CERAMIC = 0.55°C/W
QARRAY = 9.5W + (20.0W × 0.42) = 17.9W
TMAX_ARRAY = 20.0°C + (17.9W × 0.55°C/W) = 29.85°C
TDELTA_MIN = [minimum of TP2 or TP3] -TMAX_ARRAY = 27.0°C - 29.85°C = -2.85°C