Getters, technique

External gettering techniques according to Hull (1999) are (i) phosphorus diffusion gettering, (ii) Al gettering, (iii) backside damage and poly-backside seal gettering, (iv) chemical gettering, and... 

Cesium was first produced ia the metallic state by electrolysis of a molten mixture of cesium and barium cyanides (2). Subsequentiy the more common thermochemical—reduction techniques were developed (3,4). There were essentially no iadustrial uses for cesium until 1926, when it was used for a few years as a getter and as an effective agent ia reduciag the electron work function on coated tungsten filaments ia radio tubes. Development of photoelectric cells a few years later resulted ia a small but steady consumption of cesium and other appHcations for cesium ia photosensing elements followed. 

Many of the techniques available to purify alkali metals were initially developed to use with liquid sodium as a consequence of its large-scale application in liquid-metal-cooled fast-breeder reactors. These techniques can be summarized as filtration or cold trapping distillation or chemical (gettering). 

All of the following procedures were done in the nitrogen atmosphere of a Vacuum/Atmospheres HE-SS3 Dri-Lab glove box equipped with an oxygen- and water-getter and an atmosphere recirculation system. The checkers used Schlenk technique with lOO-mL flasks for the entire procedure. 

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