| 摘要 |
PROBLEM TO BE SOLVED: To realize a cold-cathode discharge vacuum gauge hardly having a sudden change point of current in the pressure-discharge current characteristic and having a discharge current substantially proportional to pressure by setting the aspect ratio of the discharge space seen from the positive electrode of a cross electromagnetic field vacuum gauge in a proper range. SOLUTION: This vacuum gauge comprises a negative electrode and positive electrode in which the aspect ratio (distance between positive and negative electrodes of discharge space)/(distance between magnetic pole pieces) of the discharge space seen from the positive electrode is set to 0.5 or more, a magnet for forming a magnetic field, a power source for applying a voltage, and a discharge current measuring ammeter. This vacuum gauge measures the pressure by measuring the discharge current.
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