science

Non-evaporable getter

Non-evaporable getter is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Non-evaporable getter rather than just read about it. In short: Non evaporable getters (NEG), based on the principle of metallic surface sorption of gas molecules, are mostly porous alloys, metallic thin films or powder mixtures of Al, Zr, Ti, V and Fe. They help to establish and maintain vacuums by soaking up or bonding to gas molecules that remain within a partial vacuum.

Key takeaways

Non-evaporable getter belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Non-evaporable getter to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Non-evaporable getter from memory before moving on to harder problems.

Reference excerpt

Non evaporable getters (NEG), based on the principle of metallic surface sorption of gas molecules, are mostly porous alloys, metallic thin films or powder mixtures of Al, Zr, Ti, V and Fe. They help to establish and maintain vacuums by soaking up or bonding to gas molecules that remain within a partial vacuum. This is done through the use of materials that readily form stable compounds with active gases. They are important tools for improving the performance of many vacuum systems. Sintered onto the inner surface of high vacuum vessels, the NEG coating can be applied even to spaces that are narrow and hard to pump out, which makes it very popular in particle accelerators where this is an issue. The main sorption parameters of the kind of NEGs, like pumping speed and sorption capacity, have low limits. A different type of NEG, which is not coated, is the Tubegetter. The activation of these getters is accomplished mechanically or at a temperature from 550 K. The temperature range is from 0 to 800 K under HV/UHV conditions. The NEG acts as a getter or getter pump that is able to reduce the pressure to less than 10−12 mbar. Non-evaporable getters, which work at high temperature, generally consist of a film of a special alloy or a monolithic porous body, often primarily zirconium; the requirement is that the alloy materials must form a passivation layer at room temperature which disappears when heated. Typical heating methods for activation include baking, RF induction, and resistive heating either external or internal to the getter. Common alloys have names of the form St (Stabil) followed by a number:

St 707 is 70% zirconium, 24.6% vanadium, and the balance iron. St 787 is 80.8% zirconium, 14.2% cobalt, and the balance mischmetal. St 101 is 84% zirconium and 16% aluminium. In tubes used in electronics, the getter material coats plates within the tube which are heated in normal operation; when getters are used within more general vacuum systems, such as in semiconductor manufacturing, they are introduced as separate pieces of equipment in the vacuum chamber, and turned on when needed. Deposited and patterned getter material is being used in microelectronics packaging to provide an ultra-high vacuum in a sealed cavity. To enhance the getter pumping capacity, the activation temperature must be maximized, considering the process limitations. It is, of course, important not to heat the getter when the system is not already in a good vacuum.

Illustrations

Worked examples

Example 1 — a first encounter with Non-evaporable getter

Start with the simplest possible case. Write down what Non-evaporable getter claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Non-evaporable getter before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Non-evaporable getter ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Non-evaporable getter

In research: Non-evaporable getter appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Non-evaporable getter in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Non-evaporable getter is common in secondary-school and first-year university syllabi. It links to neighbouring topics Alloy stubs, Vacuum, so understanding it makes those chapters shorter.
In everyday life: Look for Non-evaporable getter outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Non-evaporable getter” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Non-evaporable getter in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Non-evaporable getter means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Non-evaporable getter out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Non-evaporable getter in simple terms?

Why does Non-evaporable getter matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Non-evaporable getter?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Non-evaporable getter.