 
 <prompt> "The current strength dey depend indirectly on top the amount of wetin? Based on di last question, write small tori wey contain di answer. E fit be 1 - 20 sentences. Context:" <response>: Ion gauges dey use for ultrahigh vacuum. Dem dey come in two types: hot cathode and cold cathode. For di hot cathode version, electrically heated filament dey produce electron beam. Di electrons dey waka through di gauge and ionize gas molecules around dem. Di ions wey result dey collect for negative electrode. Di current dey depend on di number of ions, wey dey depend on di pressure for di gauge. Hot cathode gauges dey accurate from 10−3 torr to 10−10 torr. Di principle behind cold cathode version na di same, except say electrons dey produce for discharge wey high voltage electrical discharge create. Cold cathode gauges dey accurate from 10−2 torr to 10−9 torr. Ionization gauge calibration dey very sensitive to construction geometry, chemical composition of gases wey dem dey measure, corrosion and surface deposits. Dem fit invalidate di calibration by activation for atmospheric pressure or low vacuum. Di composition of gases for high vacuums fit dey unpredictable, so mass spectrometer gats dey used together with di ionization gauge for accurate measurement. 