The benefits of on-site analysis of environmental pollutants are well known, with such techniques increasing sample throughput and reducing the overall cost of pollution level monitoring. This article describes a transportable time-of-flight (TOF) mass spectrometer, based upon a converging, annular TOF (CAT) arrangement. The instrument, the transportable CAT or T-CAT is battery powered and self-contained. The vacuum chamber is never vented and is kept at a very low pressure, even during analysis. Sample gases are admitted to the mass spectrometer via a membrane inlet system. Data collection and analysis are accomplished via a portable PC. The T-CAT is capable of detection limits approaching those of more conventional, nonportable design. The device shows reasonable linearity over wide concentration ranges. Initial results indicate that the T-CAT will be capable of use in a wide range of applications, particularly for environmental monitoring. This article describes the features of the T-CAT, and presents initial results from the membrane inlet/T-CAT system.

Deep levels by proton and electron irradiation in 4H-SiC J. Appl. Phys. 98, 053706 (2005); 10.1063/1.2014941 Electrically active defects in irradiated 4H-SiC J. Appl. Phys. 95, 4728 (2004); 10.1063/1.1689731Evidence for negatively charged vacancy defects in 6H-SiC after low-energy proton implantation Low temperature annealing of 4H-SiC Schottky diode edge terminations formed by 30 keV Ar + implantation

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