A standard to test the dynamics of vacuum gauges in the millisecond range

Vacuum gauges that control fast processes in industrial applications, e.g. load locks, should immediately react to pressure changes. To study the response time of vacuum gauges to rapid pressure changes, a dynamic vacuum standard was developed where the pressure may change from 100 kPa to 100 Pa within 20 ms in a step-wise manner or within longer times up to 1 s in a predictable manner. This is accomplished by a very fast opening gate valve DN40 and exchangeable orifices and ducts through which the mass flow rate can be calculated by gas flow simulation software. A simple physical model can be used to approximate the calculations. Experiments have been performed with capacitance diaphragm gauges with improved electronics to give a read-out every 0.7 ms. Preliminary results indicate that their response time is at most 1.7 ms, but may be significantly less. •A vacuum standard with calculable pressures changing in the millisecond range is under development.•The pressure is reduced from 100 kPa to 100 Pa within a second or less (down to 20 ms).•The mass flow rate with time is calculated by extensive simulations.•Simulation results were compared with measurements and show reasonable agreement.•The response time of special capacitance vacuum gauges was measured to be less than 2 ms.