The absolute detection efficiency of a tapered microchannel plate with an open-area ratio of 90% was measured for Ne(+) with energies up to 5 keV, and comparison with the results for Xe(+) was made. As in the case of Xe(+), the maximum detection efficiency was 90%. The energy dependence of the efficiency curves normalized with respect to the open-area ratios was examined based on the scaling law proposed previously.
We developed a new mass spectrometer that can analyse multicomponent gases without fragmentation. This is essentially a time-of-flight (TOF) mass analyser in which the ion attachment method is used for ionisation. The method using this new device is referred to as “time-of-flight analysis in combination with ion-attachment” (TOFIA). TOFIA has the capability to analyse breath gas in about 10 min using the radio-frequency (RF) ion-guiding method and a multichannel scaler (MCS). The mass resolution of the trial device was unsatisfactory, but the device can be greatly improved in the future. We successfully analysed exhaled breath gases related to diseases, including ammonia, acetone, and isoprene gases. We expect that the TOFIA device developed in this work will contribute significantly to studies on the relationship between breath gas and health.
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