Search

Cryogenic environments benefit ion trapping experiments by offering lower motional heating rates, collision energies, and an ultrahigh vacuum (UHV) environment for maintaining long ion chains for extended periods of time. Mechanical vibrations caused by compressors in closed-cycle cryostats can introduce relative motion between the ion and the wavefronts of lasers used to manipulate the ions. Here, we present a novel ion trapping system where a commercial low-vibration closed-cycle cryostat is used in a custom monolithic enclosure. We measure mechanical vibrations of the sample stage using an optical interferometer, and observe a root-mean-square relative displacement of 2.4 nm and a peak-to-peak displacement of 17 nm between free-space beams and the trapping location. We packaged a surface ion trap in a cryopackage assembly that enables easy handling while creating a UHV environment for the ions. The trap cryopackage contains activated carbon getter material for enhanced sorption pumping near the trapping location, and source material for ablation loading. Using $^{171}$Yb$^{+}$ as our ion, we estimate the operating pressure of the trap as a function of package temperature using phase transitions of zig-zag ion chains as a probe. We measured the radial mode heating rate of a single ion to be 13 quanta/s on average. The Ramsey coherence measurements yield 330-ms coherence time for counter-propagating Raman carrier transitions using a 355-nm mode-locked pulse laser, demonstrating the high optical stability.

The risk of vacuum loss in linear solar heat collection elements (HCEs) is one of the major practical challenges that are facing the parabolic trough solar concentrator (PTSC) systems in concentrating solar power (CSP) plants. Despite the long-life span of CSP systems, HCEs are frequently replaced due to permeated hydrogen (due to saturation of getters) or leaked air (due to failures in end metal-to-glass welding or cracked glass shells). This study proposes a low-tech solution for boosting the performance of PTSCs with partial or lost vacuum through rotating the HCEs. A carefully validated integrated 3D optical-thermal model is developed and used to quantify the energetic and exergetic performances of PTSCs with rotated and fixed HCEs for both cases of lost and maintained vacuum. Both steady and unsteady simulations are reported using high-precision ground measurements of direct irradiance and meteorological parameters. As the rotational speed increases from 0 to 20 rad/s, the energy efficiency of PTSCs with new and damaged HCEs is improved by ∼47 and 52%, respectively, at a Reynolds number of 4000 and an inlet temperature of 350 °C. By rotating a damaged HCE at only 10 rad/s, maximum improvements of ∼26 and 53% in the useful heat gain are obtained, compared to non-rotating evacuated and non-rotating damaged HCEs, respectively, at the same operating conditions. Overall, the advantage of the proposed concept is more pronounced when the PTSC is operating at relatively low flow rates, high temperatures, or under high irradiance levels.

The article presents the results of a comparative analysis of the age characteristics of the students of educational institutions of different types as subjects of educational and professional activity. It is noted that if we consider a student of the 1st year of a higher education institution, then objectively it is possible to single out the formed self-esteem and worldview, independence. He can control his own actions and emotions. He is at the peak of his intellectual abilities. While studying in grades 10-11, he learned various types of independent work and prepared for independent search for knowledge. However, the degree of development of subject properties can be different, and of course, the process of forming subject properties is still underway. As for the 1st-year college student, the picture will be different. Self-esteem is almost formed, but it is not stable. He is less independent and cannot always control his own emotions and behavior. Only by the end of the 1st year (achievements of 16-17 years) does he begin to fully control himself. Since the formation of cognitive processes is completed, he still has to learn to control them. Unfortunately, first-year students of 15-16 years do not fully possess the skills of independent work: they do not know how to plan, work with scientific literature, and overcome serious difficulties at work. Communication with peers is important for him, and he relies more on their assessment of his own personality and activities. Therefore, it depends on communication with peers.From this it can be concluded that the students of colleges are significantly different from students of institutions of higher education, because they are at the stage of formation of subjectivity, worldview, cognitive abilities, self-esteem and self-regulation are at the stage of formation, the emotional background is unstable. In communication, a college student depends on the opinion of peers. Thus, educational and professional activity is aimed at forming the personality of a professional as a subject of professional activity: an active person who knows how to independently plan his own activities, who has self-awareness and self-regulation. A first-year college applicant is significantly different from a first-year student at a higher education institution, because he is at the stage of becoming a subject. The existing contradiction between society's high need for independent and self-realized specialists capable of active adaptation and the underdevelopment of a part of college applicants as subjects of educational and professional activity indicates an important problem - the need to form the subjectivity of first-year college applicants. Therefore, college teachers face the responsible psychological and pedagogical task of forming the student's personality as a subject of educational and professional activity. For this purpose, it is necessary to correct his self-esteem, teach him self-regulation skills, the ability to plan, organize his own activities, manage time, fully communicate and learn independently., У статті презентовано результати порівняльного аналізу вікових особливостей здобувачів закладів освіти різних типів як суб`єктів навчально-професійної діяльності. Зазначається, що студент-першокурсник коледжу значно відрізняється від студента-першокурсника ЗВО, тому що перебуває на етапі становлення суб'єктності. Отже, перед викладачами коледжу постає відповідальне психолого-педагогічне завдання формування особистості здобувача як суб'єкта навчально-професійної діяльності. З цією метою необхідно коригувати його самооцінку, навчити його навичкам саморегуляції, вмінню планувати, організовувати власну діяльність, розпоряджатися часом, повноцінно спілкуватися та вчитися самостійно.

A porous ZrFe alloy specimen was prepared as a 6 × 3 mm (diameter × thickness) disk. The reaction of the ZrFe alloy was confirmed while the whole system was maintained at a target temperature, which was increased from 150 oC to 950 oC in a 99.999% low purity nitrogen atmosphere, consisting of 10 ppm of impurity gas. Surface color, pore size, stabilized layer, and phase change were confirmed with optical microscopy, scanning electron microscopy-energy dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Micro-Raman, according to temperature. The surface color of the ZrFe alloy changed from metallic silver to dark gray as the temperature increased. In the EDS and XPS results, nitrogen component was not observed, and oxygen content increased on each surface at the elevated temperatures. In this way, the ZrFe alloy was stabilized in a low purity nitrogen atmosphere, preventing rapid nitride reactions.

LaxSr2–xNiRuO6, LaxSr4–xNiRuO8, and LaxSr3–xNiRuO7are, respectively, then= ∞, 1, and 2 members of the (Lax/2Sr1–(x/2))nSr(Ni0.5Ru0.5)nO3n+1compositional series. Reaction with CaH2, in the case of the LaxSr2–xNiRuO6perovskite phases, or Zr oxygen getters in the case of the LaxSr4–xNiRuO8and LaxSr3–xNiRuO7Ruddlesden–Popper phases, yields the corresponding topochemically reduced (Lax/2Sr1–(x/2))nSr(Ni0.5Ru0.5)nO3n–1compounds (LaxSr2–xNiRuO4, LaxSr4–xNiRuO6, and LaxSr3–xNiRuO5), which contain Ni and Ru cations in square-planar coordination sites. Thex= 1 members of each series (LaSrNiRuO4, LaSr3NiRuO6, and LaSr2NiRuO5) exhibit insulating ferromagnetic behavior at low temperature, attributable to exchange couplings between the Ni1+and Ru2+centers they contain. Increasing the La3+concentration (x> 1) leads to a reduction of some of the Ru2+centers to Ru1+centers and a suppression of the ferromagnetic state (lowerTc, reduced saturated ferromagnet moment). In contrast, increasing the Sr2+concentration (x< 1) oxidizes some of the Ru2+centers to Ru3+centers and enhances the ferromagnetic coupling (increasedTc, increased saturated ferromagnet moment) for then= ∞ andn= 2 samples but appears to have no influence on the magnetic ordering temperature of then= 1 samples. The magnetic couplings and influence of doping are discussed on the basis of superexchange and direct exchange couplings between the square-planar Ni and Ru centers.

Hermetic sealing microelectronic devices in package become more and more of a challenge for manufacturers due to the complexity of thermal management, getter integration, and material selection and interactions. Such complexity drives the original equipment manufacturer (OEM) to deliver the equipment and technology to meet manufacturers’ requirements. This study has successfully demonstrated that a vacuum reflow technology is able to deliver packages with an excellent hermetic seal. The measured leak rates of these two package types are about two orders of magnitude better than the requirement by Mil-Std 883 method 1014 specification. The result is clear that optimization of the force applied to the lid and package during seal process is essential and the force density of 5 kPa is able to produce a great hermeticity for the two packages under study. A good solder joint strength is essential to deliver a package with hermeticity but is not enough, while a weak joint strength is not possible to achieve hermeticity.

Thispaper introduces a novel, inherently simple, and all-silicon wafer-level fabrication and hermetic packaging method developed for MEMS devices. The proposed method uses two separate SOI wafers to form highly-doped through-silicon vias (TSVs) and suspended MEMS structures, respectively. These SOI wafers are then bonded by Au-Si eutectic bonding at 400 °C, achieving hermetic sealing and signal transfer without requiring any complex via or trench refill process steps. The package vacuum is measured using encapsulated MEMS resonators to be as low as 15 mTorr with the help of successfully activated thin-film getters. The combined fabrication and packaging yield is around %89 and chips still maintain a package pressure below 100 mTorr after more than 6 years. The packages show an extremely high strong bonding strength (>40 MPa) and are proved to remain hermetic after temperature cycling (25 °C-85 °C) and harsh temperature shock (5 min@300 °C) tests. The all-silicon MEMS resonators fabricated and packaged using the proposed method project up to a $2.3\times $ enhancement in the bias instability and $\sim 4\times $ in the temperature sensitivity of frequency output compared to an identical MEMS resonator fabricated using the silicon-on-glass (SOG) technology.

In this study, the effect of Al on the high temperature oxidation of Al-containing refractory high entropy alloys (RHEAs) Ta-Mo-Cr-Ti-xAl (x = 5; 10; 15; 20 at%) was examined. Oxidation experiments were performed in air for 24 h at 1200 °C. The oxidation kinetics of the alloy with 5 at% Al is notably affected by the formation of gaseous MoO3 and CrO3, while continuous mass gain was detected for alloys with the higher Al concentrations. The alloys with 15 and 20 at% Al form relatively thin oxide scales and a zone of internal corrosion due to the formation of dense CrTaO4 scales at the interface oxide/substrate. The alloys with 5 and 10 at% Al exhibit, on the contrary, thick and porous oxide scales because of fast growing Ta2O5. The positive influence of Al on the formation of Cr2O3 followed by the growth of CrTaO4 to yield a compact scale is explained by getter and nucleation effects.

International audience; Many microsensors need to operate in medium vacuum, which is obtained by low temperature vacuum packaging integrating a getter film. By a thermal activation during the sealing process, the getter film aims to compensate the outgassing of the inner surfaces of the micro-cavity and also leaks after sealing. Thin films of getter alloys were coevaporated under ultra-high vacuum on silicon wafers. They were activated by annealing at temperatures ranging from 225 °C to 400 °C, during one hour under Argon atmosphere with traces of oxidizing species. Three complementary ion beam analysis techniques were performed to obtain depth profiles and to quantify the number of atoms of the different gaseous species absorbed by the getter films: Rutherford Backscattering Spectrometry (RBS), Nuclear Reaction Analysis (NRA) and Elastic Recoil Detection Analysis (ERDA). The results show that both oxygen and hydrogen diffuse inside the getter films. However, hydrogen tends to accumulate near the interface between film and substrate and starts to diffuse inside substrate as well. We demonstrated that the sorption of hydrogen by an yttrium-based getter film is tailored by its composition and depends on its degree of oxidation.

International audience; This study investigates novel Portland cement-based mortars, developed for hydrogen/tritium trapping and radioactive waste immobilization. They incorporate a γ-MnO2/Ag2O getter powder at 10% wt (i.e. 6.8 to 7.1% vol). Compared to former patented materials, no drying or heat treatment of the materials is needed.Complementarily to X Ray Diffractometry (XRD) and thermo-gravimetry analysis (TGA), 27Al and 29Si Magic Angle Spinning Nuclear Magnetic Resonance (MAS NMR) evidences that the structure of the Portland cement solids (i.e. the C-A-S-H) is not impacted by the presence of getter, even after several month curing. Yet, Scanning Electron Microscopy coupled to Energy Dispersive Spectroscopy (SEM+EDS) shows that calcium is significantly present at the surface of the getter grains; this could affect trapping efficiency.However, after gamma irradiation with cumulated doses of 491 or 997 kGy (i.e. 23 to 46 days at 900 Gy.h−1), all mortars made with getter have a hydrogen trapping efficiency of between 77 and 96%, when compared to the irradiation of mortars made with a non-trapping γ-MnO2 powder, or to the irradiation of pure water considered alone.This means that the developed mortars display excellent hydrogen trapping efficiency, without any impact on their solid structure.

Vacuum insulation panels (VIPs) with a glass-fiber core has been considered to be difficult to operate for a long period of time, such as for building applications, because the thermal conductivity rises rapidly as the pressure increases. However, glass-fiber-core VIPs contain a material called a getter that continuously adsorbs permeated gas, and a theoretical model that considers the properties of the getter has not yet been developed. In this paper, the gas-adsorption mechanism by getters was investigated and a long-term-performance prediction model that considers the temperature dependence was proposed. Some gases were not adsorbed by the getter in the VIPs; however, a model was proposed that takes into account the non-absorbed gases by applying partial pressure to the adsorption isotherm in advance. The long-term performance of VIPs with different areas and volumes was compared with the measured values, and the validity of the calculation results was confirmed. These results show that the long-term performance of VIPs of different sizes can be accurately predicted when the getter performance is well understood.

In this paper we describe state-of-the-art approaches to the modeling of strain relaxation and dislocations in ZnSSe/GaAs (001) heterostructures, with applications to dislocation sidewall gettering (DSG) in devices. Current modeling approaches are based on the extension of the original Dodson and Tsao plastic flow model [B. W. Dodson and J. Y. Tsao, Appl. Phys. Lett., 51, 1325 (1987); Appl. Phys. Lett., 52, 852 (1988)] to include compositional grading and multilayers, dislocation interactions, and differential thermal expansion. Important recent breakthroughs have greatly enhanced the utility of these modeling approaches in three respects: i) pinning interactions have been included in graded and multilayered structures, providing a better description of the rate of strain relaxation as well as the limiting value; ii) a refined model describing the interaction length for dislocation-dislocation interactions was formulated to include jogging in compositionally-graded and step-graded layers; and iii) inclusion of back-and-forth weaving of dislocations provides a more accurate description of heterostructures containing strain reversals, such as strained-layer superlattices or overshoot graded layers. We will describe these three key advances and use reasonable estimates of the kinetic parameters for ZnSSe to explain and illustrate practical features of dislocation sidewall gettering in II-VI heterostructures.

Light- and elevated temperature-induced degradation (LeTID) of silicon wafers reduces the energy yield of photovoltaic modules in the field. A previous study demonstrated that this degradation is greatly reduced in samples with a surface textured with black silicon formed via reactive ion etching. However, the reason for this reduction is currently not understood. This article extends that result to a range of nano-textures formed using commercial metal-catalyzed chemical etching. Lifetime test structures are fabricated on multicrystalline wafers with six different chemical nano-textures and the results are compared to planar reference samples. The article demonstrates a reduction in the extent of light-induced degradation compared to planar reference samples for all six textures. The extent of LeTID is observed to reduce with decreasing front surface reflectance and increasing front surface area. The article finds that wafer thickness, phosphorus gettering, and fast-firing cannot explain the result.

This paper describes the development of a novel CPC (compound parabolic collector) evacuated tube solar collector, using a medium-temperature selective coating. The medium-temperature selective coating was obtained by co-sputtering titanium and aluminum targets. The absorptance and the thermal emittance of the heat treated coating is 0.95, and 0.04 at 80℃ respectively. The collector was optimized, using a manifold of copper U-tube with anti-oxidized coating and aluminum fin. An anti-reflection layer is added on the cover glass tube, and non-flash getter are used for maintaining the vacuum of the collector tubes. Thermal test results shown that the instantaneous efficiency based on gross area ηG can reach 0.46 at the temperature of 150℃ and the normalized temperature difference Tm* is 0.13 [(m2-°C)/W]. The experimental steam system application showed that the novel CPC solar collector can produce steam from water with temperatures about 108–145 °C during sunny days. It was also shown that the thermal performance of the solar collector did not degraded significantly.

A new, simple, low-cost technique for the preparation of solar-grade silicon, based on acid-treatment and high-temperature phosphorus-pentoxide gettering of metallurgical-grade silicon for removing the harmful metallic impurities is reported. The starting material is pulverized metallurgical-grade silicon. Purification is achieved by continuously boiling the silicon in a mixture of acids under reflux conditions for about 14 days, replacing the acid by a fresh mixture every 3-5 days. Iron content in the silicon and in the extracted acids has determined using & spectrophotometric technique. Acid leaching was found to be affective in appreciably reducing the content of harmful metallic impurities. Gettering with phosphorus pentoxide was used to achieve further purification of the acid-treated silicon. A thick paste of the acid-leached silicon 5% by weight of phosphorus pentoxide and de-ionized water was heated at 1050 oC for 4 days in a clean quartz container in air. The resulting charge was treated with hydroflouric acid to remove the phosphosilicate glass, and then cleaned and refluxed with agua regia for several days. The iron content in the silicon was further reduced to 150 - 250 ppm. The acid-leached and gettered silicon was used to produce a large area substrate using melting and unidirectional solidification, for solar cell fabrication. The substrate had a resistivity of 0.03 Ԛ c.m and was n-type, making it very suitable for solar cell fabrication.

We confirm whether Zr powders can restrain a rapid nitrification reaction and offer a stable oxidation reaction according to temperatures in nitrogen gas purification. A pellet-type, porous Zr getter is prepared (diameter: 10 and thickness: 3 mm) using Zr powder with an average particle size of 45 μm. While maintaining the whole system, the Zr getter reaction is confirmed with an increase in temperature from 150 to 550 oC at increments of 100 oC under 99.999 % purity nitrogen atmosphere comprising of 10 ppm of impurity. Surface color, pore size, stabilized layer, and phase change are confirmed with optical microscopy, SEM-EDS, Micro-Raman, and X-ray diffraction (XRD) according to the Zr getter temperature. The surface color of the Zr getter changes from metallic silver to dark gray as temperature increases. In the EDS results, the nitrogen component is not observed, and oxygen content increases from each surface at elevated temperatures. The Raman and XRD results show the oxidation layer as a result of 350 oC annealing. Therefore, the Zr getter can be applied as a nitrogen getter under 5-nine purity nitrogen atmosphere after appropriate oxidized pre-stabilization process to prevent rapid nitrification reaction.

The 3 GeV electron storage ring of the MAX IV laboratory is the first light source storage ring that has the inner surface of nearly all the vacuum chambers coated with non-evaporable getter (NEG) thin film. The vacuum and the accelerator performance have proven successful., The 3 GeV electron storage ring of the MAX IV laboratory is the first storage-ring-based synchrotron radiation facility with the inner surface of almost all the vacuum chambers along its circumference coated with non-evaporable getter (NEG) thin film. The coating provides a low dynamic outgassing rate and pumping of active gases. As the NEG coating was applied on an unprecedented scale, there were doubts concerning the storage ring performance. Fast conditioning of the vacuum system and over five years of reliable accelerator operation have demonstrated that the chosen design proved to be good and does not impose limits on the operation. The vacuum system performance is comparable with or better than that of other similar facilities around the world, where conventional designs were implemented. Observed pressure levels are low, and the electron beam lifetime is long and not limited by residual gas density. A summary of the vacuum performance is presented.

ZrB2 film plays an important role in microelectronic applications owing to its extremely high-temperature stability, excellent chemical inertness and low resistivity. Unfortunately, its electrical properties are extremely sensitive to microstructure and contaminants such as oxygen in the prepared films. Conventional strategy for the fabrication of low-content oxygen ZrB2 film requires complex ultra-high vacuum (UHV) setups. In analogy to industrial Ti-sublimation pumping, here we conceive a simple method by introducing an assisted Ti cathode sputtering in situ to trap residual gases and contaminants. This method enables high-quality ZrB2 films with low oxygen-content, good crystallinity and minimum resistivity of 265 μΩ cm to be achieved at a modest vacuum level environment without complex UHV devices and intentional substrate heating system.

A novel solid-liquid inter-diffusion (SLID) bonding process is developed allowing to use thin layers of the Au-Sn material in wafer-level microelectromechanical systems (MEMS) packaging while providing a good bonding strength. The bond material layers are designed to have a robust bond material configuration and a metallic bond with a high re-melting temperature, which is an important advantage of SLID bonding or with its alternative name, transient liquid phase (TLP) bonding. The liquid phase in SLID bonding is the gold-rich eutectic liquid of the Au-Sn material system, where the bonding temperature is selected to be 320 °C for a reliable bonding. The average shear strength of the bonds is measured to be 38± 1.8 MPa. The hermeticity of the package is tested with the He-Leak test according to MIL-STD 883, which yields a leak value lower than $0.1 \times 10^{-9}\,\, atm.cm^{\textit {3}}/s$ . The vacuum inside the package without a getter is calculated as 2.5 mbar after cap wafer thinning. The vacuum level is well preserved after post-processes such as annealing at 400 °C and the dicing process. These results verify that thin layers of Au-Sn materials can be used reliably with the SLID or TLP bonding technique using the new approach proposed in this study. [2020-0353]

Zeolites such as sodalite and zeolite A have been used for decades to encapsulate radioactive 85Kr for long-term storage. However, recent reports of zeolite getters removed from hot cells after ove...

The present work summarizes the results of previously known, as well as the latest sorption measurements, which were carried out on IIA metal alloys in the form of films, powders and macrobodies with a monolithic structure. Analysis of these data made it possible to construct an empirical sorption model, according to which the corrosive decomposition of reactive alloys is one of the driving forces of the sorption process. This model provides a qualitative description of the sorption behavior of these alloys in a gas environment and can be useful in solving practical problems in the field of vacuum and gas technologies.

High Temperature Reverse Bias (HTRB) reliability failure is found to be caused by huge amount of undesirable hydrogen proton (H+) ions from packaging resin or external environment, while Temperature Humidity Bias (THB) reliability failure is known to be caused by moisture accumulation. A commonly known method of improving HTRB is by increasing phosphorus concentration in the PMD layer to enhance device gettering capability against H+. However, this is usually achieved at the expense of THB reliability as excessive phosphorus on the PMD surface gives rise to moisture accumulation and caused THB failure. In this paper, we performed a series of experiments to uncover two elements in PMD that are responsible to getter H+, which are Phosphorus-Oxygen-Hole-Center (POHC) and dangling bonds. We also discussed 2 possible ways to boost these H+ gettering elements to improve HTRB reliability without the adverse impact on THB reliability: Utilization of Plasma Enhanced Chemical Vapor Deposition (PECVD) Phospho-Tetraethyl-Orthosilicate (PTEOS) in PMD layer to replace the commonly used Atmospheric Pressure Chemical Vapor Deposition (APCVD) or Sub Atmospheric Chemical Vapor Deposition (SACVD) Boro-Phospho-Tetraethyl-Orthosilicate (BPTEOS) and the introduction of Tetraethyl-Orthosilicate (TEOS) capping layer on PMD layer. Both methods have proven to greatly alleviate HTRB and THB reliability marginality problems.

In the present study, the overheating degradation of as-deposited Mo/Si multilayers was investigated. Technological low-temperature furnace annealing at 300 °C for 1 h was used to simulate the overheating process. A multilayer Mo/Si structure with a period of 21.7 nm was created by DC magnetron sputtering. The dopant distribution in the as-deposited and annealed multilayers was studied by the dynamic- and 3D TOF-SIMS and SNMS methods. Periodic changes in multilayers were studied by the X-ray reflectometry method. It is shown that the cause of the Mo/Si multilayers degradation are oxygen gettering by the Mo/Si interfaces and the silicon diffusion into molybdenum layers due to the Mo/Si interface deformation with the appearance of randomly located places of penetration.

The Zr1-xCox(x=0, 0.25, 0.53, 0.63, 1) thin films were deposited on quartz substrate using magnetron co-sputtering of Zirconium and Cobalt targets in confocal geometry. A constant pulsed direct current (PDC) on Zirconium and radio frequency (RF) of various powers on Cobalt target were applied to vary the concentration of Co in the Zr1-xCox film. The film composition was quantified using EDX measurements. The hydrogen storage capacity of these films was studied using an in-house developed hydrogen adsorption setup, in which the electrical resistivity of the film was monitored as a function of hydrogen partial pressure and temperature. The films' surface morphology and crystal structure before and after hydrogenation were characterized using atomic force microscopy and grazing incidence X-ray diffraction techniques using synchrotron radiation, respectively. An increase in the particle size after hydrogenation was observed for all the films. An increase in resistivity was also observed due to the absorption of hydrogen in all the compositions. The near stoichiometric film Zr0.47Co0.53 showed the highest hydrogen absorption level at 200 oC at all partial pressures. However, a decrease in the response at temperatures higher than 200 oC was observed in the film containing a Co concentration. The mechanism for the increase in resistivity of the film on hydrogenation is explained. Keywords: ZrCo alloy, hydrogen getter, magnetron co-sputtering, four-probe resistivity, thin film.

In order to develop a scientifically grounded technology for production of porous getters, there appears the necessity to apply highly sensitive methods for determining the activation temperature, which are compatible with the standard magnetron pumping technology. In this study, a complex technique for determining the activation temperature for porous getters is proposed using the experimental scheme simulating the conditions of porous getter activation in accordance with the standard exhaust tube pumping technology. Under the conditions of the simulation of physicochemical processes in the volume of the heated magnetron housing under pumping, the model of the formation of a gas load on the interior pumping equipment is considered. It is shown that, according to the theory of composite chemical reactions, thermal desorption flows are generated by either the theory of consecutive reactions or the theory of parallel-consecutive reactions. The sorption capacity of porous getters is determined from a plot as the time–temperature dependence of the mass yield of composite chemical reactions of interaction between the gas load and the surface and bulk of a getter tablet. A getter tablet’s change in mass is recorded using the microbalance of a vacuum thermogravimetric unit uninterruptedly at the frequency of one measurement a second throughout the entire period of measurements. The sensitivity threshold of the microbalance is 10–5 g and the maximum mass is 5 g. Using the theory of parallel-consecutive reactions, for the first time, the minimum temperature of thermal activation of a porous getter of a Ti–V (30 at %) alloy is determined, which is the main technological parameter when interior pumping equipment is employed. For the nonisothermal part of the standard heat treatment plot, at the heating rate of 10°C/min and the specified vacuum conditions, the minimum activation temperature is 393°C. For estimating the changes in the roughness of the free surface of a getter washer subjected to interior saturation in a hydrogen medium, scanning electron microscopy is used. Cracks and microsized tetragonal single crystals are found, which might be titanium hydrides TiН2. It is established that crack formation has a positive effect on the getter’s sorption activity due to the appearance of new atomically clean surfaces. However, cracking can contribute to the crumbling of the getter tablet. Therefore, the hydrogen gas load is the factor that limits the durability of the getter.

An absolute MEMS capacitance vacuum sensor with a full range of (1-1000) Pa has been designed, fabricated and tested. The working principle of the capacitance vacuum sensor is explained and its fabrication process is introduced. For obtaining high sensitivity, the sensor’s pressure-sensing diaphragm with large width-to-thickness ratio is manufactured using the silicon-on-insulator (SOI). A silicon buffer block is adopted to improve the linearity of the sensor and prevent the pressure-sensing diaphragm from being damaged due to overload. The sensor is packaged by anodic bonding process in a certain high vacuum environment to form a sealed cavity, in which the vacuum degree is maintained by the non-evaporable getter (NEG) film deposited on the buffer block surface. The absolute pressure measurement of the packaged sensor has been performed with a vacuum measurement system. The tests results show that the capacitance-pressure curve is piecewise linear in the full range (1-1000) Pa. And the sensor exhibits high stability and reproducibility. The maximum sensitivity of the sensor is 33.03 fF/Pa, while the resolution can reach 0.5 Pa. Moreover, the temperature characteristic of the sensor has been evaluated, and it turns out that the effect of temperature on the sensor is quite small in a certain temperature range. [2020-0276]