getter

get·ter

G0109000 (gĕt′ər)n. A material added in small amounts during a chemical or metallurgical process to absorb impurities.

getter

(ˈɡɛtə) n1. a person or thing that gets2. (General Physics) a substance, usually a metal such as titanium, evaporated onto the walls of a vacuum tube, vessel, etc, to adsorb the residual gas and lower the pressurevb (General Physics) (tr) to remove (a gas) by the action of a getter

get•ter

(ˈgɛt ər)

n. 1. a person or thing that gets. 2. any substance introduced into a partial vacuum to combine chemically with the residual gas in order to increase the vacuum. [1325–75]

getter

Past participle: gettered
Gerund: gettering

Imperative
getter
getter

Present
I getter
you getter
he/she/it getters
we getter
you getter
they getter

Preterite
I gettered
you gettered
he/she/it gettered
we gettered
you gettered
they gettered

Present Continuous
I am gettering
you are gettering
he/she/it is gettering
we are gettering
you are gettering
they are gettering

Present Perfect
I have gettered
you have gettered
he/she/it has gettered
we have gettered
you have gettered
they have gettered

Past Continuous
I was gettering
you were gettering
he/she/it was gettering
we were gettering
you were gettering
they were gettering

Past Perfect
I had gettered
you had gettered
he/she/it had gettered
we had gettered
you had gettered
they had gettered

Future
I will getter
you will getter
he/she/it will getter
we will getter
you will getter
they will getter

Future Perfect
I will have gettered
you will have gettered
he/she/it will have gettered
we will have gettered
you will have gettered
they will have gettered

Future Continuous
I will be gettering
you will be gettering
he/she/it will be gettering
we will be gettering
you will be gettering
they will be gettering

Present Perfect Continuous
I have been gettering
you have been gettering
he/she/it has been gettering
we have been gettering
you have been gettering
they have been gettering

Future Perfect Continuous
I will have been gettering
you will have been gettering
he/she/it will have been gettering
we will have been gettering
you will have been gettering
they will have been gettering

Past Perfect Continuous
I had been gettering
you had been gettering
he/she/it had been gettering
we had been gettering
you had been gettering
they had been gettering

Conditional
I would getter
you would getter
he/she/it would getter
we would getter
you would getter
they would getter

Past Conditional
I would have gettered
you would have gettered
he/she/it would have gettered
we would have gettered
you would have gettered
they would have gettered

getter

[′ged·ər] (chemistry) scavenger (physical chemistry) A substance, such as thallium, that binds gases on its surface and is used to maintain a high vacuum in a vacuum tube. A special metal alloy that is placed in a vacuum tube during manufacture and vaporized after the tube has been evacuated; when the vaporized metal condenses, it absorbs residual gases. Also known as degasser.

getter

In vacuum or gas-filled tubes, it is a small, ring or cup-shaped device containing a powdered metal that reacts strongly to oxygen. When the tube is sealed, the getter is fired (heated) to further evacuate a vacuum tube or to remove impurities from the gas. Firing causes the getter material to oxidize and absorb any free oxygen in the tube, which would otherwise oxidize the active electrodes and decrease the tube's life. Tubes with graphite-based electrodes do not use getters, because the graphite itself absorbs oxygen.

In a vacuum tube, the location of the getter is sometimes identified by a shiny silver deposit behind the glass, which is residue from the firing. The metal used in the getter depends on tube manufacturer, type and composition. Barium is an excellent oxygen absorber and is used in tubes with a fired getter. Zirconium and titanium, also used as getter material, oxidize from the tube's self-generated heat and do not require firing.