Experimental apparatus Digital camera Humidity Thermocouple Blower fan

Experimental apparatus Digital camera ×: Humidity ×: Thermocouple Blower fan Hygrometer Visualization area Orifice Frosting section Neutron beam Temperature control heat exchanger Air flow Electronic balance

Brine Fin-Tube heat exchanger 10 mm 50 mm Experimental apparatus Material：Pure aluminum Neutron beam 95 mm 105 mm Experimental condition Ambient temperature [deg. C] 20. 8 Inlet air temperature [deg. C] 6 Air flow rate [ℓ/min] 250 Brine temperature [deg. C] -19 Frosting time [min. ] 145

Neutron radiography Neutron source Beam port Nuclear reactor KUR（B 4 port） Thermal output 1 MW Guide tube length 11. 7 m Guide tube cross section 10（D）× 74（D’） mm Typical spectrum 1. 2 Å Neutron flux refrigerator 1× 107 n/cm 2 s Camera CCD camera “PIXIS 1024 B” （Princeton Instruments） Imaging array Frosting section Frame 1024× 1024 pixels Lens “APO MACRO 180 mm F 3. 5” （SIGMA corporation） Exposure 30 sec.

Experimental results X Y 0 0 ５ 600 pixel ４ ３ ２ １ 1024 1. 1 g/cm 2 0 X Y ①: (243, 745) ②: ( 60 , 630) ③: (243, 535) ④: (135, 480) ⑤: ( 60 , 420) 各点における着霜量の時間変化