A low x-ray background low temperature specimen stage for biological microanalysis in the TEM.

The side entry specimen stage described in this paper is a development of a specimen stage for use at room temperature in the JEOL JEM 100 and 200 series transmission electron microscopes. The earlier specimen stage was designed to ensure that the extraneous instrumental contribution to thin specimen X-ray spectra is both small and quantifiable. As well as having a low X-ray background the new stage will also maintain the specimen at temperatures sufficiently low (down to 100 K) to minimize the loss of organic material due to electron irradiation.

Preparation of cryosections with a modified Sorvall MT2B ultramicrotome and cryoattachment.

The Sorvall MT2B ultramicrotome and cryoattachment were modified to extent the duration of cutting and to overcome problems in tissue preparation. Microtome and cryochamber were encased and surrounded by an atmosphere of dry nitrogen gas at room temperature. A specially designed cold block sited within the box close to the microtome enabled tissues to be trimmed at low temperatures in the dry environment.

Optimum conditions for cryoquenching of small tissue blocks in liquid coolants.

Three approaches were taken with the aim of defining the optimum conditions of rapid cryopreservation in liquid quenchants. In a theoretical approach, two mathematical models were used. The first is of value in defining the absolute maximum rates of cooling which could be achieved at various depths in the tissues.