Since the hydrogen content causing delayed fracture (hydrogen embrittlement) of some high strength steels is in the order of 0.01 weight ppm, accurate measurement is required. The present situation of hydrogen gas desorption analysis for the studies of hydrogen embrittlement of high strength steels is reviewed, and evaluation techniques of hydrogen embrittlement property using constant load test and slow strain rate test of hydrogen precharged specimens in conjunction with hydrogen desorption analysis are illustrated. In addition, measurement of hydrogen entry from the atmospheric corrosion environment is presented. Both critical hydrogen content for delayed fracture, obtained by means of the above mentioned tensile tests, and hydrogen content from environment are important parameters to evaluate delayed fracture susceptibility of high strength steels. The results of round robin tests of measurement of hydrogen content in steels using thermal desorption analysis is also introduced.

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  For many years since 1990's, we have developed thermal desorption spectrometer (TDS) as ex-situ analysis tool, used in wide fields of process control and development of new materials such as semiconductor and flat display devices, polymers, catalyst, metals and so on. Recently TDS is required not just for qualitative or relative comparison but for quantification of thermally-desorbed gasses.
  This paper describes the performance and the several key points for quantification in TDS measurements; (1) repeatability of measurements and simple calibration method using referenced materials of ion implanted Si, (2) stability of sensitivity in quadrupole mass spectrometer (QMS), and (3) mass discrimination of QMS sensitivity and its correction method. The correction method for mass discrimination of QMS is successfully demonstrated. Entire results indicate that the TDS measurement provides a good quantitative evaluation of many kinds of outgassing species not only hydrogen and water vapor.

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  Thermal desorption spectroscopy (TDS) is an important technique for investigation of adsorption, absorption, and desorption behaviors of atoms and molecules on surfaces. We briefly summarize the general procedure of TDS in surface science studies, and then we introduce our recent study of hydrogen transport across a Pd-Au alloy surface measured by TDS as an example. By combining the TDS data with other surface analysis, we found that hydrogen penetrates and desorbs through a site related to surface Pd atoms. We also demonstrate a molecular cap effect of CO, where a small amount of CO adsorption greatly changes the hydrogen absorption and desorption behavior by blocking the entrance and exit site.

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  Low-temperature crystallization of Si, Ge and Si_XGe_1−X films by SR-soft x-ray irradiation using short undulator light is examined. By setting the photon energy to that of the core electron orbital, the crystallization is examined experimentally and discussed theoretically from a view point of Ge diffusion. The temperature during the crystallization of Si, Ge or Si_0.5Ge_0.5 by soft x-ray was 80 to 140 degree C lower than that by the conventional rapid thermal annealing. The elementary process of the soft x-ray irradiation is thought to be the atom-diffusion following the localized excitation of the core-electrons and the generation of Coulomb repulsion. For the low-temperature crystallization, the quasi-nuclei are formed via the elementary process.

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  Evacuated multilayer insulation (MLI) for thermal insulation of the laser interferometer mirror, which is cooled to cryogenic temperatures, is used in the large-scale cryogenic gravitational wave telescope KAGRA. This MLI consists of alternating layers of aluminized polyethylene terephthalate (PET) and lightweight fibrous PET spacers. In a vacuum, however, water molecules outgassed from MLI might degrade the interferometer performance owing to their condensation on the mirror. We have developed new MLIs with thinner PET spacers, whose mass is 30% lighter than that of the conventional one, to reduce outgassing rate. In this study, outgassing rate of new MLIs was measured from the pressure decrease rate in a vacuum chamber for 300 hours. After 100 hours of vacuum testing, its outgassing rate was about half of that for the previous MLI, and comparable to that of electropoloshed stainless steel (SUS304).

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