Mass spectrometer is one of the essential techniques for vacuum science and technology and surface science and technology. Recently, vacuum not only with low pressure but also with high quality is required in the research and industry. In this special issue, basic theory, applications, international standardization, and recent advances in miniaturization and high-resolution analysis are published.

Industrial vacuum equipment requires a clean surface free from contamination, depending on the intended degree of vacuum from the handling of parts. A quadrupole mass spectrometer is widely used as a method for analyzing outgass in a vacuum vessel. However, in order to perform more quantitative quality control, it is necessary to measure the accurate mass of the gas component and specify the components. In this study, accurate mass measurement was performed on outgass from various vacuum equipment using GC-MS and TOFMS, and it was possible to measure the gas components that could not be measured by the conventional method. By using this equipment, it is expected to improve vacuum quality and product quality.

When residual gas analysis in the UHV and XHV regions are performed with a general quadrupole mass spectrometer (QMS), it is difficult to perform accurate gas analysis due to outgassing from the sensor ion source. We have developed an ultra-low outgassing QMS with an improved ion source to enable highly accurate residual gas analysis.

Miniaturization of the instruments is desiring in the industrial field because it enables easy mount to the process, less mounting space, handy tool, less requirement of electrical energy etc. The Small mass spectrometer system which includes analyzer and vacuum system is also effective tool for various fabrication processes. Atonarp Inc. have developed and released small mass spectrometer system for the molecular controlling process. Feature of this system are small, fast, easy operation, real time process monitoring, and also edge device for the big data analysis. This paper describes basis of small mass spectrometer and some engineering application examples of the mass spectrometer system including Lyophilization, thin film deposition, and thin film etching.

Residual gas analyzers (RGAs) using quadrupole mass spectrometers (QMSs) are essential for many applications and research in vacuum industries, semiconductor process monitoring and water endpoint detection, space exploration, glass coating, environmental screening, petroleum processing and planetary aeronomy studies among others. During the past decades, QMSs have been variously carried out towards miniaturizing mass spectrometer systems, sensor and electronics devices without sacrifice of performance. In this study the design of a miniature quadrupole mass spectrometer having a small total volume of 6 cm³, including electron ionization ion source, quadrupole filter and faraday cup detector is solution to meet the needs. The characterization of a miniature array of 16 rods to obtain nine sets of quadrupole and to increase signals is described.

We describe design and a comprehensive evaluation of the performance of miniature quadrupole arrays.

In small and medium-sized display for mobile devices such as smartphones, organic EL displays using organic light-emitting diodes (OLED) are increasing. Therefore vacuum evaporation and plasma enhanced chemical vapor deposition (PECVD) equipment are key technologies in manufacturing of OLED devices. We developed new process gas monitor for PECVD process which meet customer's new demand. It was confirmed that the lifetime of the ion source is longer than conventional one.

Two ISO standards related to quadrupole mass spectrometer (QMS) are introduced ; one is ISO 14291:2012 Definitions and specifications for quadrupole mass spectrometer and the other is ISO/TS 20175:2018 Characterization of quadrupole mass spectrometers for partial pressure measurement. This paper consits of two parts. This first part includes the background that these ISO standards were developed and the definition of sensitivity and relative sensitivity factor of QMS.

Two ISO standards related to quadrupole mass spectrometer (QMS) are introduced ; one is ISO 14291:2012 Definitions and specifications for quadrupole mass spectrometer and the other is ISO/TS 20175:2018 Characterization of quadrupole mass spectrometers for partial pressure measurement. This paper consits of two parts. This second part includes the definition of parameters to specify QMSs such as minimum detectable partial pressure, minimum detectable concentration, dynamic range, interference effect, mass resolution, and so on. The methods to evaluate these parameters is also introduced.

This review reports many aspects of existing issues and its solutions in a RGA sensor head in detail. The issues that disturb RGA performances can be categorized into four different groups based on their phenomena. The first one is thermal desorption mainly from ion source. The second is electron stimulated gas desorption from the anode surface in the ion source, from the envelope inner surface around the ion source and from the electron multiplier surface of the detector. The third is ion stimulated desorption from the ion extraction plate. The fourth is ion sputtering and film deposition both in the ion source and around the electron multiplier. In this review, important operational parameters and other points which affect RGA performances and measurement results are also discussed.

Quadrupole mass spectrometer is widely used, for example in the laboratory and the factory. However the essential intricate principle of the mass separation is not enough to be understood. This paper try the understandable explanation for the principle using the Mathieu functions and the suggestion by Wolfgang Paul.