Figure 5
(a) Photograph of a set of devices used for preparing frozen-hydrated biological specimens, and a custom-made freezing device. (b) Magnified view of the humidity controlling chamber. A cassette holder is filled with moist air from the HUM-1, and is removable from the main body of the chamber. (c) Photograph of the flash-freezing device just before plunging the specimen disk into the liquid-ethane bath. Liquid ethane is produced by blowing ethane gas onto the wall of an aluminium cap cooled by liquid nitrogen. The temperature of liquid ethane is kept above the melting point by using a film heater of 7 Ω (Sakaguchi Dennetsu, Japan) connected to a power supply of 24 V as schematically illustrated in the inset on the upper right. The inset on the lower right is a photograph of a disk container to store flash-frozen specimen disks in liquid nitrogen (Yasuda Shoten, Japan). (d) Specimen holder and plates used to bring specimen disks from the liquid-nitrogen bath to the vacuum chambers of diffraction apparatus. Plates shown in the left photograph are used as illustrated on the right. Two neodymium magnets of 1.5 mm diameter and 3 mm height are buried in the specimen holder. An aluminium adaptor for carrying four specimen disks of diameter 3 mm is fixed to the specimen holder by a covering plate with four holes. The other covering plate is used to fix a silicon specimen disk with nine SiN windows to the specimen holder. |