Hiroshi Saeki - Residual currents detected with a correcting electrode in a modified Bayard-Alpert hot-cathode-ionization gauge

Version 1

      Publication Details (including relevant citation   information):

      Rev. Sci. Instrum. 79(5), 055102-1 - 055102-4 (2008).

      This article is related to H. Saeki's presentation "Reduction in   pressure-measurement errors caused by x-ray currents in a   hot-cathode-ionization gauge" at IVC-17/ICSS13 and ICN+T 2007,   Stockholm, Sweden, 2007.

      PACS:

                                                                                                          
            07.30.Dz              Vacuum gauges      
            85.60.Ha              Photomultipliers; phototubes and photocathodes      
            82.45.Fk              Electrodes      
            84.70.+p              High-current and high-voltage technology: power systems;         power transmission lines and cables      

      Abstract:

      A nude-type hot-cathode-ionization-gauge head with correcting   electrode and shield tube, succeeded in reducing practical   pressure-measurement errors caused by an influx of photoelectrons   in a synchrotron radiation environment. In the development of   this modified Bayard–Alpert hot-cathode-ionization gauge,   experimental results showed that a basic ion current generated   around the correcting electrode by emission from the gauge   filament, was proportional to an emission current (less than 10%   of the normal emission current) detected with a grid of   correcting electrode, and that differences between estimated and   measured basic ion currents in a pressure range of higher than   10−8 Pa order meant   pressure-independent residual currents detected with the   correcting electrode. By using calculated forward x-ray currents,   these results also showed that the estimated residual currents   with the correcting electrode were mainly caused by x rays from   the grid of the hot-cathode-ionization-gauge head and the grid of   correcting electrode, and that the x-ray currents with the   correcting electrode only caused by x rays from the grid of the   hot-cathode-ionization-gauge head were about 11% of the nominal   x-ray current of the ionization-gauge head. Furthermore, they may   suggest that an expected residual current with the collector can   be calculated by using the estimated residual current with the   correcting electrode, and that this ionization gauge has an   additional function to reduce pressure-measurement errors caused   by residual currents, though it is necessary to test the   ionization gauge in an extremely high-vacuum environment under   the x-ray limit of the gauge.

      Address (URL): http://rsi.aip.org/resource/1/rsinak/v79/i5/p055102_s1