A cell suitable for use with an atomic clock and a method for making the same, the cell including: a silicon wafer having a recess formed therein; at least one amorphous silicate member having an ion mobility and temperature expansion coefficient approximately that of silicon sealing the recess; and, an alkali metal containing component and buffer gas contained in the recess. Further, the method of reducing the variation with the specific accuracy causes an increase in the size of the circuit and power consumption. The load interface circuit provides a modulated load current in response to the continuous current. The recess of each plate surrounds a locating peg projecting centrally from the base of the recess and is bounded by an annular rim, such that the annular rims of the plates are arranged to contact one another at a predetermined limit of sliding movement of the plates over the core.