Small sensitive pressure transducer for use at low temperatures

A sensitive diaphragm-type pressure transducer suitable for use at very low temperatures is described. This device was optimized for pressures up to 3.5 MPa, but sensors for other pressure ranges can be readily manufactured. The external pressure deflects two sapphire disks which causes a change in capacitance between the platinum electrodes sputtered on the disks. The transducer can easily resolve changes of 1 Pa at 3.5 MPa, while reproducibility and hysteresis, though not fully tested yet, are better than 10 Pa. The transducer is 610 μm thick and 8 mm diameter.