Statement on the article by C. D. Suen et al. (J. Vac. Soc. Jpn. 37 (1994) 700)

In order to develop an ion gauge with a very low outgassing rate and a very low gas sorption rate, we have been studying in the electron oscillator mini-ion gauge with a ring anode since the early 80's. We have published a handful of paper on our achievements in Vacuum Science and Technology (China). I planned to attend the 28th AVS to present our paper but plan did not come true due to financial difficulties. In the latter part of 1983, we invited about 30 distinguished Chinese experts in vacuum measurement to attend a special meeting, we devoted to discussion of the electron oscillator mini-ion-gauge. As a result, we believe Chinese researchers in this field are familiar with each others' work. We were surprised to read the paper by Suen et al. which was presented at XHV '94. We were especially surprised to learn that “a new mini-axial-emission ionization gauge (MAEG) with a ring anode, which is a modification of the AEG and the oscillator mini-ion-gauge (OMG), is described in this paper.” and “The original plate collector and spiral grid of AEG are replaced by a needle (0.15×5mm, W) and a ring anode (0.2×6mm, Mo), respectively.” We would like to emphasize that the “new” ionization gauge presented by Suen et al. bears close similarity to the gauge described in papers we presented in 1984. The only differences are minor : for example, Suen et al. choose different operating voltages and electrode materials. Hence it is our conviction that the ion gauge presented by Suen et al. is not a new gauge.