Titanium pump performance and outgassing mechanism

Titanium pump performance (1) Ultimate pressure: 10-8 Pa (2) pumping speed: Titanium pump pumping speed and anode voltage and magnetic field strength, when the magnetic field pumping speed is also large, corresponding to the optimal pumping speed of the anode voltage is also high. Common titanium pump pumping speed 25 liters / second, 5 liters / second. For situations requiring a large pumping speed, pumping speed can reach 50 liters / second, 100 liters / second and so on in parallel with the basic structural units. (3) Start pressure: 10-2 Pa (4) Life expectancy: a, cathode depletion life Cathode titanium plate due to sputtering through the pump can not be used. b, the anode spalling life titanium anode deposited within the film thickness is too large will produce spalling, resulting in irregular strong pressure changes in the pump, so that the pump can not be used. c, the anode sucking the life of the anode adsorption and dissolution of a large number of helium, hydrogen, when it reaches saturation, the pump can no longer adsorb gas. In normal use, sputtering ion pump life of up to tens of thousands of hours. Gas Removal Mechanism (1) Removal of Active Gas The removal of gases such as N2, O2, CO and CO2 mainly depends on the chemical adsorption of the titanium film deposited on the inner wall of the anode cylinder. (2) The extraction of hydrogen Hydrogen removal of chemical adsorption, but also diffusion, absorption, dissolution. (3) The removal of inert gas Exclusion of inert gas, mainly by ion "buried" by ionized inert gas ions bombard the cathode, the following three conditions: a, ions directly into the cathode, or Into the titanium deposition layer on the anode plate opposite the edge of the cathode; b, the oblique ions cut into the cathode surface, the ions and titanium are thrown off and deposited around the cathode plate or elsewhere; c, ions did not break into the plate , But the electrons are taken from the cathode and recombined into neutral atoms, which are then reflected into the titanium film on the inner surface of the anode. Titanium pump power Titanium pump power supply is high resistance power, the no-load output voltage between 3 ~ 7KV, but the load current is large, the output voltage dropped to 400V or so. General sputtering ion pump uses 5KV voltage doubler rectifier power supply. Can be used to flow through the titanium anode and cathode discharge current reflects the vacuum of the space. Sputtering ion pump in the rated voltage and magnetic field discharge current Iion (mA) and the pressure P (Torr) has a certain curve. So by ion pump power can reflect the size of the pressure. Pump power panel shows: output DC high voltage and titanium pump discharge current.