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Getter

A getter is a reactive material intentionally deposited or placed within a vacuum system to chemically absorb and remove residual gases, thereby maintaining or enhancing the vacuum quality.^[1] These materials function by reacting with gas molecules—such as hydrogen, oxygen, or water vapor—that strike their surface, preventing contamination and pressure buildup in sealed environments.^[2] Getters have been integral to vacuum technology since the early 20th century, evolving from simple metallic deposits in incandescent bulbs to sophisticated alloys used in modern devices.^[3] Getters are classified into two primary types: evaporable and non-evaporable. Evaporable getters, often consisting of metals like barium or titanium, are heated to vaporize and form a thin film on internal surfaces, where they actively sorb gases during operation.^[4] In contrast, non-evaporable getters (NEGs) are typically alloys such as zirconium-vanadium-iron or titanium-based materials that operate at lower temperatures and are activated by baking the system to clean their surface for gas sorption.^[5] NEGs are particularly valued for their long-term stability and ability to handle a broad spectrum of gases without requiring continuous evaporation.^[6] The applications of getters span electronics, lighting, and scientific instrumentation. In vacuum tubes and cathode-ray tubes, getters ensure reliable electron flow by eliminating trace gases that could cause arcing or degradation.^[2] They are also essential in particle accelerators, where ultra-high vacuum is critical for beam stability, and in micro-electro-mechanical systems (MEMS) for maintaining hermetic seals in sensors and actuators.^[7] Ongoing advancements focus on nanostructured getters to improve efficiency and compatibility with emerging technologies like fusion reactors and space instruments.^[4]

Fundamentals

Definition and Purpose

A getter is a deposit of reactive material placed inside a vacuum system to complete and maintain the vacuum by chemically reacting with and absorbing residual gas molecules.^[1] These materials, typically metals or alloys, function by combining with gases through processes such as chemisorption or chemical reaction, thereby removing them from the system.^[3] The primary purpose of a getter is to scavenge residual gases, including hydrogen, oxygen, nitrogen, water vapor, carbon monoxide, and carbon dioxide, that outgas from internal materials or enter through minor leaks, thus preventing pressure rises that could compromise system performance.^[1] In vacuum technology, such maintenance is essential for achieving and sustaining high vacuum conditions in devices like electron tubes to enable unimpeded electron flow and prevent cathode contamination or arcing, and ultra-high vacuum (UHV) conditions, defined as pressures below 10^{-9} Torr, in particle accelerators to minimize beam-gas interactions that scatter particles.^[8]^[9] Getters can effectively reduce pressure in sealed systems from approximately 10^{-3} Torr, following initial evacuation, to below 10^{-7} Torr, with some configurations achieving even lower levels in UHV applications.^[10] This capability is particularly vital in hermetically sealed devices where ongoing gas evolution must be counteracted over the operational lifetime.^[11] Getters exist in forms such as evaporable and non-evaporable types, each suited to specific vacuum regimes.^[1]

Operating Principles

Getters function by sorbing gas molecules from the vacuum environment, primarily through two mechanisms: physisorption and chemisorption. Physisorption involves weak physical adsorption via van der Waals forces, with binding energies typically below 10 kcal/mol, resulting in short sojourn times that limit its effectiveness at room temperature unless cryogenic cooling is applied.^[4] In contrast, chemisorption entails irreversible chemical bonding, often covalent or metallic, with higher binding energies exceeding 10 kcal/mol (e.g., ~20 kcal/mol for H₂ on titanium), enabling stable compound formation such as oxides (e.g., TiO₂, ZrO₂) or hydrides (e.g., ZrH₂) that effectively trap active gases like oxygen, nitrogen, hydrogen, carbon monoxide, and water vapor.^[4]^[12] The reactivity of getter materials stems from their atomic properties, particularly in metals like barium, titanium, and zirconium, which possess electron configurations that provide available valence electrons for strong bonding with electronegative gases (e.g., barium: [Xe] 6s²; titanium: [Ar] 3d² 4s²; zirconium: [Kr] 4d² 5s²). These metals also feature low work functions (e.g., ~2.7 eV for barium, ~4.3 eV for titanium), facilitating electron transfer and dissociative chemisorption on the surface, where gas molecules break apart and form low-vapor-pressure compounds that do not readily desorb.^[12]^[13] This high affinity is selective, excelling with reactive (active) gases but ineffective against noble gases like helium and neon, which lack suitable orbitals for chemical bonding and thus exhibit near-zero sticking probabilities.^[4] Pumping speed quantifies the rate at which a getter removes gas, defined as S = \frac{dV/dt}{P}, where S is in liters per second, dV/dt is the volumetric throughput, and P is the gas pressure; typical values range from 0.1 to several L/s per cm² of getter surface for common gases.^[4] The effective speed depends on the sticking probability \alpha (0.1–0.3 for H₂ on titanium at low coverage) and follows the kinetic theory limit (specific pumping speed per unit area of getter surface):

S = \alpha \times 3.64 \sqrt{\frac{T}{M}} \quad (\text{L/s} \cdot \text{cm}^2)

where T is temperature in Kelvin and M is molecular mass.^[4] Saturation capacity, the total gas sorbed before exhaustion, is surface-limited at ~5 × 10¹⁴ molecules/cm² for a monolayer but can extend via bulk diffusion in porous or alloyed getters, reaching 10¹⁸–10¹⁹ molecules/cm² depending on material.^[4]^[12] Efficiency is influenced by several factors, including temperature, which accelerates reaction rates and diffusion (sojourn time \tau = \tau_0 e^{E/RT}, with activation energy E and R = 1.98 \times 10^{-3} kcal/mol·K) but risks desorption of weakly bound species above ~300–400°C; increased surface area through roughness or porosity (speed proportional to porosity²) enhances both speed and capacity; and gas type, with optimal performance for diatomic or polar molecules but minimal for inert species.^[4] Contamination or oxide layers on the getter surface can reduce \alpha by blocking active sites, necessitating clean conditions for maximal performance.^[4]

Historical Development

Early Discoveries

The earliest observations related to the getter concept emerged from vacuum discharge experiments in the mid-19th century. In 1858, German physicist Julius Plücker conducted studies using Geissler tubes with platinum electrodes, noting that certain residual gases reacted with the platinum cathode to form a black deposit on the glass walls, effectively reducing the gas pressure and approaching a higher vacuum state.^[14] This phenomenon, described as gases combining with the electrode material to produce compounds that adhered to the tube's interior, provided the foundational insight into gas absorption by reactive surfaces in low-pressure environments, though Plücker did not explicitly develop it as a technique.^[14] By the early 1900s, practical applications of getters appeared in incandescent lighting to mitigate filament evaporation and bulb blackening. Austrian chemist Franz Skaupy pioneered the use of chemical getters, such as halogen compounds of metals (e.g., thallium chloride), incorporated into metal filament lamps around 1910; these materials were activated during operation to sorb evaporated tungsten and residual gases, extending lamp life and maintaining clarity.^[15] Skaupy's innovation, detailed in his 1910 patent filing (granted in 1915), marked the first systematic employment of getters in commercial devices, addressing gas evolution from filaments in evacuated bulbs.^[15] In parallel, early vacuum tubes employed non-metallic getters to manage residual gases during the 1910s. Materials like phosphorus and lime (calcium oxide) were applied in detectors such as the WD-11 tube, introduced around 1922, where they chemically bound oxygen and other contaminants released during manufacturing or operation, preventing ionization and improving tube stability.^[16] These rudimentary getters, often coated on the tube stem, represented an initial step toward high-vacuum maintenance in radio applications. The 1920s saw a pivotal shift to metallic getters in radio tubes, driven by the need to counteract outgassing from advanced filaments. As thoriated tungsten filaments became standard by 1921, they released gases like oxygen that degraded performance; General Electric responded by integrating magnesium getters, which more effectively sorbed these evolved species, enabling reliable amplification in receiving sets.^[17] This transition from non-metallic to metallic materials improved vacuum integrity and supported the rapid expansion of broadcast radio.^[17]

Key Advancements in the 20th Century

In the 1920s, the invention of flashed evaporable getters represented a pivotal advancement in vacuum tube manufacturing, transitioning from rudimentary gas removal techniques to more effective materials that maintained high vacuum levels over extended periods. General Electric pioneered the use of getters in production as early as 1917–1918 with magnesium-based variants, and by the early 1920s, they had become standard in tubes like the UV-199 and UV-201A, initially employing red phosphorus for initial gas sorption during sealing. Barium-based evaporable getters, developed toward the end of the decade, offered superior reactivity with residual gases such as oxygen, nitrogen, and water vapor, significantly reducing outgassing and enabling reliable operation in receiving and transmitting tubes. This innovation extended tube functionality, supporting the rapid growth of radio broadcasting and early electronics.^[17]^[18] The 1930s and 1940s saw the commercialization of advanced getter alloys, with KEMET Laboratories (established in 1919 as a Union Carbide subsidiary) expanding production in 1930 to include barium-aluminum alloys, which provided stable, high-yield barium evaporation for superior gas trapping. These getters were integral to vacuum tubes powering radar systems, radios, and communication devices during World War II, where KEMET supplied approximately 80% of Allied needs, enhancing signal reliability in harsh operational environments. By optimizing vacuum integrity, such getters contributed to achieving lifespans exceeding 10,000 hours in receiving tubes under normal service conditions, a marked improvement over earlier designs prone to premature failure from gas contamination.^[19]^[20]^[21] The emergence of non-evaporable getters (NEG) in the 1950s addressed limitations of evaporable types in sustained, high-vacuum applications, with SAES Getters—founded in 1940 by Paolo della Porta—developing air-stable alloys like BaAl₄ that required activation without full evaporation, paving the way for zirconium-based variants. These NEG materials, known since the late 1950s, offered distributed pumping capabilities ideal for particle accelerators and space systems, where continuous gas sorption prevented beam instability and equipment degradation without the mess of evaporated films. Early zirconium NEG prototypes, such as those alloyed with aluminum (e.g., 84% Zr–16% Al), demonstrated high capacity for sorbing active gases like CO, H₂, and O₂ at room temperature post-activation.^[12]^[22] By the 1960s, getters achieved widespread adoption in consumer and industrial electronics, particularly color televisions and microwave tubes, where innovations like SAES Getters' Total Yield Flash Getter (introduced in 1966) dramatically reduced failure rates from gas contamination by extending picture tube lifespans from 300 hours to over 10,000 hours. In color TV cathode-ray tubes, these barium-based flashed getters ensured uniform vacuum maintenance, minimizing ion bombardment on cathodes and preserving image quality over years of use. Similarly, in microwave tubes for radar and communication, NEG and hybrid getter systems lowered outgassing-related breakdowns, supporting higher power handling and operational reliability in military and broadcast applications.^[23]^[24]

Types of Getters

Evaporable Getters

Evaporable getters consist of reactive metals that are heated to vaporize within a vacuum system, allowing the vapor to condense as a thin film on the internal surfaces, thereby creating a fresh, highly active layer for gas sorption. This process, often performed after initial pumping and sealing, enables the getter material to chemically bind residual gases through chemisorption, maintaining low pressures in sealed devices such as vacuum tubes.^[13]^[25] The primary materials used in evaporable getters are alkaline earth metals, including barium, strontium, and magnesium, often alloyed for improved handling and stability. Barium, typically sourced from a BaAl₄ alloy mixed with nickel powders and contained in a stainless steel dispenser, is the most common due to its high reactivity and efficiency. Strontium serves as an alternative in applications requiring low vapor pressure, while magnesium is employed in mercury-vapor tubes despite its comparatively lower gettering power. These metals react avidly with active gases; for instance, barium combines with oxygen to form barium oxide (BaO) and with hydrogen to form barium hydride (BaH₂), along with compounds like barium nitride (Ba₃N₂) from nitrogen.^[13]^[25]^[4] Evaporable getters offer high initial pumping speeds, reaching up to approximately 44 L/s per cm² for hydrogen at room temperature due to near-unity sticking probabilities on the fresh film, enabling total speeds of 1000 L/s or more in systems with large surface areas like television tubes. Their simplicity makes them ideal for one-time activation in sealed consumer devices, where they provide compact, cost-effective gas removal without ongoing power needs post-deposition. Subtypes include bulk forms, consisting of solid alloy pieces heated in a filament or dispenser, and pre-applied coatings, where thin films are deposited prior to sealing for targeted applications.^[4]^[13] However, these getters have finite sorption capacity, typically saturating after exposures on the order of 10^{-5} Torr·L per unit area as the reactive surface becomes covered by stable compounds, rendering them non-regenerable and unsuitable for long-term or ultra-high vacuum environments requiring repeated use. They also fail to sorb inert gases like helium or argon, limiting their scope to reactive species.^[25]^[26]

Non-Evaporable Getters

Non-evaporable getters (NEGs) are solid-state sorbents composed primarily of transition metal alloys, such as those based on titanium, zirconium, and vanadium, designed to chemically bind active gases in vacuum environments without undergoing evaporation. These materials operate by forming stable compounds with gases like hydrogen, oxygen, carbon monoxide, and nitrogen upon activation, which exposes a fresh metallic surface for sorption. Unlike evaporable getters that deposit a consumable film, NEGs maintain their physical form, typically as strips, powders, pills, or thin-film coatings, allowing for repeated use in high-vacuum applications.^[27] A prominent example is the zirconium-vanadium-iron (Zr-V-Fe) alloy family, including the widely used St 707 composition of 70 wt% Zr, 24.6 wt% V, and 5.4 wt% Fe, which enables activation at moderate temperatures around 400°C to achieve effective gettering without requiring excessive heat. Other variants, such as St 101 (primarily Zr-V), demand higher activation temperatures but offer complementary performance profiles for specific gas mixtures. These alloys leverage the high reactivity of group IV transition metals to dissociate and absorb gas molecules at the surface and in the bulk, with surface area enhancements from porous structures or roughening further boosting efficiency.^[28]^[29] NEGs provide key advantages in ultrahigh vacuum (UHV) systems, where they support pressures down to 10^{-12} Torr by offering high sorption capacities, particularly for hydrogen at up to approximately 0.01 Torr·L/mg for safe operation to avoid embrittlement, enabling long-term maintenance of low gas loads without mechanical components. Their regenerability through reheating restores pumping capability, making them ideal for distributed pumping in complex setups like particle accelerators and space instruments, where they can handle cumulative gas loads over extended periods.^[3]^[1]^[27]^[30] However, NEGs exhibit slower pumping speeds for non-reactive gases like helium and argon, as sorption relies on chemical reactivity rather than physical entrapment, limiting their utility in mixed-gas environments without supplementary pumps. Additionally, their effectiveness depends on contamination-free assembly, as exposure to hydrocarbons or oxides can poison the surface, reducing initial sorption rates and necessitating careful bakeout procedures.^[31]^[3]

Activation Processes

Flashed Getter Activation

Flashed getter activation is a one-time process used to vaporize evaporable getter materials within a vacuum device, allowing the material to deposit on internal surfaces and immediately begin scavenging residual gases such as oxygen, nitrogen, and carbon dioxide.^[13] This step typically follows the initial evacuation of the vacuum tube to ensure the getter effectively removes any remaining gases that could degrade performance.^[13] The activation involves rapidly heating the getter, often composed of barium or barium-aluminum alloys mounted on a support structure, to temperatures between 900°C and 1300°C for a duration of a few seconds.^[13] Heating is commonly achieved through radio-frequency (RF) induction coils positioned externally around the tube or, in some cases, electron bombardment, which induces an exothermic reaction to facilitate evaporation.^[13]^[32] A controlled firing cycle, such as 2.5 seconds, ensures complete vaporization without excessive duration that could compromise the process.^[32] During flashing, the evaporated material condenses on the cooler glass walls, forming a characteristic silvery mirror-like deposit that serves as a visual indicator of successful activation.^[13] In vacuum tubes, this process produces a noticeable glow from the heated getter material and its reaction with residual oxygen, confirming the consumption of gases and establishment of a high vacuum.^[13] Once activated, the deposited film remains chemically active at room temperature, binding gases through chemisorption without significant re-evaporation, and maintains effectiveness up to approximately 200°C during device operation.^[13] Proper execution requires shielding to prevent getter vapor from depositing on critical components like insulators or lead-in wires, which could cause electrical issues.^[13] Over-flashing or misalignment of the heating source risks incomplete wall coverage, material waste, splashing, arcing, or reduced getter yield, potentially leading to suboptimal vacuum maintenance.^[33]^[32]

Non-Evaporable Getter Activation

The activation of non-evaporable getters (NEGs) involves a controlled heating process, typically referred to as baking, to remove surface passivation layers and expose fresh, reactive metallic surfaces for gas sorption. This is achieved by diffusing adsorbed gases, such as oxygen and carbon from oxides and carbides, into the getter's bulk material under vacuum conditions. Standard NEG alloys, like Zr-V-Fe (e.g., St 707), require temperatures of 300-500°C for initial activation, with durations ranging from minutes to hours depending on the system size and desired efficiency.^[12]^[27] Advanced alloys, such as Ti-Zr-V or Zr-based thin films, enable lower activation temperatures of 150-250°C, often over extended periods like 24 hours, to minimize thermal stress on sensitive components.^[31]^[34] This process can be repeated multiple times—up to hundreds of cycles for bulk NEGs—without significant material loss, as each cycle exposes new surface area while preserving the getter's overall capacity.^[31]^[35] The activation occurs in distinct stages to optimize performance. Initial activation employs higher temperatures (e.g., 400-500°C for standard alloys) to reduce surface oxides by promoting their diffusion into the bulk, thereby cleaning the surface and enabling chemisorption of active gases.^[12]^[36] Subsequent reactivation, often at slightly lower temperatures (e.g., 300-450°C), focuses on restoring hydrogen pumping capability by desorbing and diffusing previously sorbed H₂ deeper into the material, allowing the surface to resume effective sorption.^[27]^[12] In applications like particle accelerators, NEG strips are commonly activated in situ using resistive heating, where electrical current is passed through the supporting strip (e.g., constantan) to achieve uniform temperature distribution without external ovens.^[37]^[38] Monitoring the activation process is essential to verify efficacy and ensure ultra-high vacuum (UHV) conditions. Pressure gauges, such as residual gas analyzers (RGAs), are used to track improvements in base pressure, often observing a temporary rise to 10⁻⁴–10⁻⁵ mbar during heating due to gas release, followed by a sharp decline as the getter activates.^[27] Pumping speed measurements, via techniques like hydrogen pulsing, confirm restoration of sorption capacity, with reactivation typically recovering up to 90% of the initial performance per cycle for films like Ti-Zr-Hf-V.^[39]^[34] A key challenge in NEG activation is preventing surface contamination, particularly from hydrocarbons, which can poison the reactive sites and degrade pumping efficiency. Organic outgassing during heating must be minimized through thorough system bakeouts or plasma cleaning prior to activation, as hydrocarbons form stable carbides that resist diffusion.^[12] Additionally, hydrogen evolution during the process can embrittle the material if not managed, though advanced low-activation alloys mitigate this by operating at reduced temperatures.^[27]^[31]

Applications

In Vacuum Tubes and Lamps

Getters have played a crucial role in maintaining the vacuum integrity of vacuum tubes, particularly through the use of evaporable barium-based materials in receiving tubes prevalent from the 1930s to the 1970s. These flashed getters, typically alloys like barium-aluminum, were activated during manufacturing by heating to evaporate a thin film that coated the inner surfaces, effectively sorbing residual gases and outgassing from the filament to prevent arcing and cathode poisoning.^[17]^[40] In devices such as television and radio sets, this process extended operational life to thousands of hours by minimizing gas buildup that could degrade performance.^[40] In incandescent lamps, early getters employing magnesium emerged around the 1910s to sustain vacuum quality in metal-filament bulbs, particularly those with tungsten filaments. These materials were introduced as small quantities within the bulb envelope, vaporizing during operation to chemically react with and remove trace oxygen and other gases that would otherwise cause filament evaporation and bulb blackening by depositing tungsten on the glass walls.^[41] By sorbing evaporated tungsten and residual contaminants, magnesium getters helped prolong lamp efficacy and reduce premature darkening, marking an advancement over earlier chemical gettering methods like phosphorus.^[42] For microwave tubes, such as klystrons used in high-power applications, non-evaporable getters (NEGs) provide stable vacuum conditions essential for electron beam integrity. NEG coatings, often based on zirconium or titanium alloys, are applied to internal surfaces and activated at moderate temperatures to continuously pump active gases without the need for evaporation, ensuring low-pressure environments that support reliable microwave amplification.^[43] This approach is particularly vital in electrostatically focused klystrons, where even minor gas contamination could disrupt beam focusing and output stability.^[43] The integration of getters significantly lowered failure rates in vacuum tube-based electronics during World War II, enabling robust performance in critical systems like Allied radio communications.^[20] By addressing vacuum degradation—the primary cause of tube failures—getters enhanced reliability under harsh operational conditions, contributing to wartime technological advantages.^[17] With the advent of transistors in the mid-20th century, widespread use of vacuum tubes and their associated getters declined sharply by the 1960s, though getters retain a legacy in specialty tubes for high-power and microwave applications where solid-state alternatives remain limited.^[44]^[45]

In Accelerators and High-Vacuum Systems

In particle accelerators, non-evaporable getters (NEGs) play a critical role in achieving and sustaining ultra-high vacuum (UHV) conditions necessary for beam stability and minimal particle scattering. In the CERN Large Hadron Collider (LHC), thin-film coatings of Ti-Zr-V alloys are applied to the inner walls of the beam pipes along the 27 km circumference to provide distributed pumping, particularly for hydrogen (H₂), the dominant residual gas. These coatings enable effective H₂ sorption through chemisorption and diffusion into the bulk material after activation, maintaining pressures below 10⁻¹⁰ Torr across the km-scale vacuum system despite outgassing from beam-induced desorption.^[46]^[47] NEGs are also essential in X-ray tubes, photomultipliers, and infrared (IR) detectors, where they mitigate outgassing from internal components to preserve sensitivity and longevity in high-vacuum environments. In photomultiplier tubes, compact NEG formulations with low activation temperatures (around 350–450°C) are integrated to sorb reactive gases without compromising the device's miniaturization, ensuring stable electron multiplication under UHV.^[48] For IR detectors, sintered NEG pills based on Zr-V-Fe alloys maintain vacuum in Dewar modules, preventing thermal leaks from residual gases and enabling cryogenic operation for cooled focal plane arrays. In space-based instruments and cryogenic sensors, NEGs support long-term UHV by continuously pumping evolved gases, thus avoiding performance degradation over mission durations.^[49] Getters further enhance vacuum insulation in cryogenic systems and fusion reactors, where ultra-low pressures are vital for thermal efficiency and isotope handling. In vacuum insulated panels (VIPs) used for cryogenics, Zr-based NEGs adsorb water vapor and hydrogen permeation from enclosing materials, sustaining internal pressures below 10⁻³ Torr to minimize heat transfer in multilayer insulation. In fusion reactors like ITER, NEG materials facilitate tritium recovery by selectively sorbing tritiated species from purge gases in the tritium extraction system, operating at moderate temperatures to achieve high recovery efficiency without oxidation processes.^[50]^[51] In micro-electro-mechanical systems (MEMS), getters are used to maintain hermetic seals in sensors and actuators by sorbing residual gases and moisture within sealed cavities, ensuring long-term reliability and performance in miniaturized vacuum environments.^[52] Ion pumps often incorporate titanium sublimation getters to reach extreme UHV levels, combining ion burial of non-reactive gases with chemical gettering of active species. Titanium sublimation pumps, which evaporate Ti filaments to form fresh getter films on chamber walls, boost hydrogen pumping speeds by orders of magnitude when paired with sputter ion pumps, enabling pressures as low as 10⁻¹² Torr in systems like surface science chambers and particle storage rings. This hybrid approach ensures robust, bakeable vacuum maintenance over extended periods.^[53]^[54]

Modern Developments

Advanced Materials

Since the early 2000s, innovations in non-evaporable getter (NEG) alloys have focused on enhancing pumping efficiency, particularly for hydrogen, through optimized compositions in the Zr-V-Fe family. Variants such as the St 172 alloy, developed by SAES Getters, consist primarily of zirconium, vanadium, and iron, enabling effective room-temperature pumping after activation for ultra-high vacuum (UHV) and extreme high vacuum (XHV) applications.^[55] This alloy supports high pumping speeds for active gases like H₂ (up to 2000 l/s in larger pump configurations) and single-run capacities exceeding 2000 Torr·L for H₂, making it suitable for distributed pumping in particle accelerators and space systems.^[55] In the 2020s, advancements in NEG thin films have further improved hydrogen sorption performance, with new generations exhibiting enhanced absorption capacity compared to earlier formulations. For instance, SAES Getters introduced materials in 2022 that boost hydrogen uptake, addressing demands in high-precision vacuum environments.^[56] These thin-film developments, often deposited via sputtering, support sustained UHV in compact devices.^[57] Nanostructured forms of getters, including powders and coatings, have emerged to maximize surface area for gas sorption, particularly in micro-electro-mechanical systems (MEMS). By refining powders to the nanoscale, such as in Zr-Co-based intermetallics, the effective surface area increases significantly, enhancing activation at lower temperatures and overall pumping rates.^[58] These structures are integrated into MEMS packaging to maintain long-term vacuum integrity without compromising device miniaturization.^[59] Efforts toward eco-friendly NEG options emphasize compositions with reduced or eliminated rare-earth elements, relying instead on abundant metals like Zr, V, and Fe to minimize environmental impact. The global NEG materials market reflects this shift, projected to grow at a compound annual growth rate (CAGR) of approximately 5.3% through 2032, driven by demand in sustainable vacuum technologies for electronics and energy systems.^[60] In the 2010s, low-activation NEGs operable at around 150°C were advanced, ideal for heat-sensitive devices like MEMS and sensors, where traditional higher-temperature activations (above 300°C) pose risks.^[61] These formulations maintain robust sorption for H₂ and CO at reduced baking temperatures, broadening applicability in integrated circuits and portable instrumentation.^[62]

Emerging Technologies

In recent years, non-evaporable getter (NEG) thin-film coatings have gained prominence in synchrotron facilities for enabling distributed pumping, where the getter material is applied directly to vacuum chamber walls to enhance gas sorption without discrete pumps. These coatings, typically composed of titanium-zirconium-vanadium alloys, provide high pumping speeds for hydrogen isotopes and other reactive gases while minimizing secondary electron yield and photon-stimulated desorption, crucial for maintaining ultra-high vacuum (UHV) in beamlines.^[63]^[64] For instance, in the Large Hadron Collider (LHC) at CERN, NEG thin films have been scaled up for production and integrated into vacuum systems, supporting upgrades aimed at increasing luminosity by distributing pumping capacity across extended chamber surfaces.^[63] Heated getter purifiers have seen significant advancements by 2025, particularly in semiconductor manufacturing, where they achieve impurity levels below 1 part per billion (ppb) for gases like hydrogen, nitrogen, and rare gases. These systems employ zirconium-based alloys heated to elevated temperatures (typically 300–600°C) to chemically bind contaminants such as O₂, H₂O, CO, CO₂, and hydrocarbons, ensuring the ultra-pure process gases required for advanced node fabrication in chips.^[65]^[66] Innovations include dual-stage designs that combine heated getter beds with catalytic stages for broader impurity removal, reducing operational costs and extending service life in high-volume fabs.^[67] Getters play a vital role in fusion and quantum technologies, addressing unique vacuum challenges in these fields. In tokamaks, such as those under development for ITER, non-evaporable getters like Zr-V-Fe alloys (e.g., St-707) are used for tritium handling, reversibly storing the isotope in getter beds to manage inventory, prevent permeation, and mitigate poisoning from species like tritiated ammonia during plasma operations.^[68]^[69] In quantum computing, ion getter pumps—often combining sputter ion mechanisms with titanium sublimation—maintain extreme high vacuum (XHV, <10⁻¹² mbar) in ion trap or neutral atom systems, capturing residual gases to preserve qubit coherence without introducing vibrations or heat.^[70]^[71] These pumps, integrated into compact UHV chambers, support scalable architectures by providing passive, power-efficient pumping for cryogenic environments.^[72] As of 2025, plasma-aided activation techniques for ZrVFe getters enable rapid activation within 5 minutes, stabilizing chamber pressures below 150 Pa and improving efficiency in UHV systems.^[73] The market for high-strength getters, which withstand mechanical stresses in demanding UHV applications, is projected to reach USD 134.14 million by 2034 at a compound annual growth rate (CAGR) of 5.8% as of 2025 estimates, reflecting broader adoption of UHV technologies to ensure reliability in manufacturing processes and long-duration missions.^[74]

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KEMET getters, found inside of vacuum tubes, were essential in pushing technology forward through the 1930s and 1940s.
[21]
[PDF] Getting the Most out of Vacuum Tubes - Pearl HiFi
Informed scientists and engineers have frequently stated that the life of a vacuum tube in normal service should exceed 5,000 or even 10,000 hours. The fact ...
[22]
[PDF] in situ studies of volatile molecules trapping in zirconium alloy - CORE
Non-evaporable getters come in the form of powdered metals or alloys, or deposited thin films of a few micrometers in thickness. In the case of powders, they ...
[23]
[PDF] History and potential of Non Evaporable Getter (NEG) technology
The development of particle accelerators pushed the development of NEGs with low activation temperature and in the form of thin film coatings. These coatings ...Missing: 1950s | Show results with:1950s
[24]
[PDF] BROCHURE DEF2_TAGLIATO2005.qxd - Gas Purifiers
Launch of Total Yield Flash Getters, extending color TV tube lifetime from. 300 to 10,000 hours. Our Strategy. SAES Getters Group's business strategy builds on ...Missing: failure | Show results with:failure
[25]
[PDF] Kinetics of Growth and Sorption Properties of Evaporable Barium ...
In this research the thin barium getter films have been prepared on glass substrates by thermal evaporation ... If the film area is large, the total pumping speed ...
[26]
[PDF] METHODS FOR SATURATION ASSESSMENT IN THE LHC NEG ...
Evaporable getter pumps are based on chemisorption of reactive gases on the surface of a ... -1, 2) 5·10-5 Torr·l·s-1. ·m. -1, 3) 5·10-4. Torr·l·s-1. ·m. -1, 1981 ...
[27]
[PDF] NEG pumps: Sorption mechanisms and applications - arXiv
Getter materials in bulk getter pumps bind gas by chemical reaction. Thus, they must be chemically reactive towards residual gases typically occurring in ...
[28]
Hydrogen adsorption characteristics of Zr57V36Fe7 non-evaporable ...
One commonly used non-evaporable getter manufactured by SAES GETTERS, St707, is a typical ternary alloy: Zr57V36Fe7, which composed of 70% Zirconium, 24.6% ...Missing: advantages | Show results with:advantages
[29]
[PDF] Getter (NEG) Pumps Using NEG Pills
can be pumped by chemical adsorption on NEG surface. ✓ Advantages of NEG pumps are oil free, evaporation free, sputtering free, sublimation free,.Missing: limitations | Show results with:limitations
[30]
[PDF] Non-Evaporable Getters
Oct 19, 2011 · ○ History of using the getter. ○ Gas-solid combinations ... Types of NEGs (SAES getters). VS-2, 18-19 October 2011, Ricoh Arena ...Missing: 1950s | Show results with:1950s
[31]
Induction Getter Firing - Ambrell
A flashed getter, made of reactive material, is heated with induction and the activated material oxidizes, condenses on the cool vessel walls in a thin coating.
[32]
Method for vaporizing getter material in a vacuum electron tube
This invention relates to a novel method for vaporizing getter material inside a vacuum electron tube and particularly, but not exclusively, to a novel method ...<|control11|><|separator|>
[33]
Testing the activation temperature of non-evaporable Ti-Zr-Hf-V ...
Among various NEGs, TiZrV films are widely used and can be fully activated by heating at 180 °C for 24 h. When the pumping speed of the film returns to about 90 ...Missing: resistive | Show results with:resistive
[34]
[PDF] Non-evaporable getter (NEG) technology for HV and UHV applications
May 29, 2025 · Non-evaporable getter (NEG) technology uses solid materials that pump chemically-active gases by forming stable chemical bonds on their surface.
[35]
Novel Non-Evaporable Getter Materials and Their Possible Use in ...
Dec 1, 2020 · Getter materials are able to chemically adsorb gas molecules on their surface, therefore are widely used in the Ultra and Extreme High Vacuum ( ...Missing: chemisorption | Show results with:chemisorption
[36]
[PDF] MASTER - OSTI
Activation is done by resistive heating of the constantan support strip which also serves as the heat source during in-sltu bakeout. The NEG strips mounted ...
[37]
[PDF] Non-Evaporable Getters : from Pumping Strips to Thin Film Coatings
Activation of the St 101. NEG requires heating to 750°C for about ½ hour; in the case of LEP, this is done by passing a current of 90 A through the strip.
[38]
[PDF] In situ effective pumping speed measurements as a tool for non ...
Areas of. NEG applications were recently expanded into vacuum devices with relatively high-pressure levels (up to 10-7 Torr) by the invention of high capacity ...
[39]
Text Dump — Vacuum Energy
Vacuum Energy's getters are engineered to keep hydrogen concentrations at or below a safety limit of 0.2% in order to prevent explosion risks.
[40]
Getters : From Light Bulbs to Accelerators - SlideServe
Apr 16, 2013 · ... incandescent lamps (1870s). Edison Light bulbs last longer !!True ... Evaporable Getters - Magnesium • Use • Mg is one of the 1st getter ...
[41]
2yr.net - History Of The Incandescent Lamp
Franz Skaupy, an Austrian chemist, invented the use of getters in metal filament ... TUNGSTEN LAMP WITH SKAUPY'S "GETTER", 1912. The chemicals called ...Missing: 1900s | Show results with:1900s
[42]
The use of a non-evaporable getter pump in the processing of a 2 ...
The use of a non-evaporable getter pump in the processing of a 2 kW electrostatically focused klystron amplifier☆ ... After bake-out a large microwave tube ...
[43]
Vacuum Tubes: The World Before Transistors - Engineering.com
Jan 19, 2018 · Despite the emergence of the transistor, vacuum tubes aren't completely extinct, and they remain useful in a handful of niche applications. For ...
[44]
Historical development and future trends of vacuum electronics
Sep 7, 2012 · Then in the 1950s, electronic tubes were gradually replaced by transistors ... tubes per year in 2008 and a continuous further decline. LCD ...
[45]
[PDF] H2 EQUILIBRIUM PRESSURE WITH A NEG-COATED VACUUM ...
Aug 4, 2006 · Non Evaporable Getter (NEG) coating is used in the Large Hadron Collider (LHC) room-temperature sections to ensure a low residual gas pressure ...
[46]
Ti–Zr–V non-evaporable getter films: From development to large ...
Non-evaporable getter (NEG) alloys after dissolution of their native oxide layer into the bulk are able to pump most of the gases present in ultra-high ...
[47]
a new generation of compact photomultipliers - ScienceDirect.com
Due to the compact design of CPM, the use of a highly effective non-evaporable getter with a low activation temperature is the only possibility. In this case, ...
[48]
Performance of non-evaporable getter to maintain vacuum of Dewar ...
Performance of non-evaporable getter to maintain vacuum of Dewar module of infrared focal plane detector and its application ... Research of performance for St ...Missing: space telescopes
[49]
Residual gas analysis in vacuum insulation panel (VIP) with glass ...
Getter works by adsorbing and absorbing residual gases to maintain high vacuum in VIP. Common getters, such as zirconium (Zr) based or barium (Ba) based getters ...
[50]
Novel Getter Materials for Tritium Recovery in Fusion
Dec 1, 2020 · This work suggests an alternative application of these materials to fusion nuclear reactors, where there is the need to recover small amount of tritium.
[51]
https://www.mdpi.com/1420-3049/25/23/5675
[52]
Ultra-High Vacuum pumps Edwards
We offer a range of ion pumps, NEG-Ion combination pumps, titanium sublimation pumps, non-evaporable getter pumps and accessories through Gamma Vacuum.
[53]
NEXTorr® UHV Pumps | Compact NEG + Ion Pump for Ultra-high ...
Two NEG-based series are available to meet different performance needs: NEXTorr® “D” Series, built around the St 172 (Zr-V-Fe) NEG alloy, proven in UHV/XHV ...Missing: temp | Show results with:temp
[54]
Non Evaporable Getter Materials Navigating Dynamics ...
In stock Rating 4.8 (1,980) Jul 1, 2025 · 2022: SAES Getters announced a new generation of NEG materials with improved hydrogen absorption capacity. 2021: Grinm launched a new range ...
[55]
Lifetime of non-evaporable getter thin films over repeated activation
Nov 28, 2024 · quired to achieve better pumping speed and capacity. This study looks at two samples each activated 15 times. at 160 and 200 °C respectively, ...Missing: 2020s | Show results with:2020s
[56]
Preparation and sorption characteristics of Zr–Co–RE getter films
Moreover, with refinement of the Zr3Co powder to the nanoscale regime, the real surface area of the synthesized nanostructured powders increases drastically.
[57]
The Study of Different Structuring Techniques for Creation of Non ...
Nanostructured getters made by sputtering are of developed surface, high sorption capacity and low temperature of activation, but are much thinner than sintered ...
[58]
Non Evaporable Getter Materials Market Size 2025-2032
The Non Evaporable Getter Materials Market size was estimated at USD 637.33 million in 2024 and expected to reach USD 669.45 million in 2025, at a CAGR 5.32% to ...
[59]
Development of low-cost, high-performance non-evaporable getter ...
When activated by baking at 150 °C, an NEG pump using oxygen-free Pd/Ti evacuates H2 and CO efficiently at room temperature, and its pumping speeds for H2 ...
[60]
[PDF] Getters - U.S. Particle Accelerator School
Jan 23, 2015 · Pumping speeds usually increase at higher sorption temperature. January 19-23 2015. Page 38. 38.
[61]
Ti–Zr–V non-evaporable getter films: From development to large ...
Aug 5, 2025 · Non-evaporable getter (NEG) thin films are routinely applied to accelerator beamlines to provide distributed pumping where the geometry makes ...Missing: VAT | Show results with:VAT
[62]
[PDF] The use of NEG pumps and coatings in large vacuum systems
Their main limitation is the activation procedure that implies a heating process up to. 350–400°C (in the case of SAES St 707 alloy) and the relatively high ...
[63]
GT2 - Tronic Purity, Inc.
It efficiently removes impurities like H2O, O2, H2, CO, CO2, CH4, and N2 (rare gases only) to levels below one part per billion (ppb) using a heated getter and ...
[64]
Pure - ASDevices
Our proprietary dual-stage purification design unlocks better purification and superior performance. With a second vessel operating at a lower temperature, the ...Missing: 2025 advancements<|separator|>
[65]
[PDF] High-purity Hydrogen: Guidelines to Select the Most Suitable ...
The final achievable purity and the impurities removed are the same for the single column and the dual column regenerable purifiers, down to less than 1 ppb ( ...
[66]
Tritium-related surface effects in tokamaks - ScienceDirect.com
Nonevaporable getters have wide applicability for tritium handling systems. From this view point, the activation process of the Zr-V-Fe getter (St-707) and ...
[67]
Fully reversible storage for tritium - ITER
Jan 11, 2013 · In ITER parlance, the vessel containing the uranium tritide is called a "getter bed." A key design objective for the ITER storage and delivery ...
[68]
Extreme High Vacuum (XHV) Reduces Computational Energy Costs ...
Nov 13, 2024 · Gettering technology is used to provide high pumping rates, using passive components that dissipate no power. An ion pump captures those gases ...Missing: vacuums | Show results with:vacuums
[69]
Quantum Technology - VACOM
We support your projects with, among other things, special vacuum chambers, specially coated optics and ion getter pumps from our MERKURION product series. With ...Missing: vacuums | Show results with:vacuums
[70]
Quantum Computing - SAES High Vacuum
Achieve ultra-high vacuum for quantum computing and sensing with SAES NEG pumps and UHV chambers. Stable, clean systems for cryogenic and atomic ...Missing: vacuums | Show results with:vacuums
[71]
High-Strength Getter Market Size to Attain USD 134.14 Million by 2034
The global high-strength getter market, valued at USD 76.33 million in 2024, is projected to reach USD 134.14 million by 2034, growing at a 5.8% CAGR as demand ...Missing: EVs space