An assembly for use in a high-sensitivity atomic sensor, the assembly comprising: an alkali vapor cell (904, 1503); at least one illumination source (902, 1501) configured to emit light when activated, the emitted light having a first predetermined range of wavelengths; a light collector capable of collecting light in the first predetermined range of wavelengths; and a plurality of optical elements arranged such that (a) light emitted from the at least one illumination source is directed to the alkali vapor cell, and (b) light emerging from the alkali vapor cell is directed to the light collector; a generally planar electrical insulator (901, 1507) having a top and a bottom, the top and the bottom being opposed to one another, wherein at least one of the alkali vapor cell (904, 1503), illumination source (902, 1501), or an optical element is supported upon the generally planar electrical insulator; a top trace on the top of the insulator (901, 1507); a bottom trace on the bottom of the insulator (901, 1507); and a through trace, the insulator (901, 1507) defining a via from the top to the bottom, the through trace contacting both the top trace and the bottom trace and passing through the via so that the top trace, bottom trace and through trace form a single electrically conductive element; wherein the top trace and the bottom trace are congruent so that a current along the single electrically conductive element tends to create a self-cancelling magnetic field; and wherein the top trace, or the bottom trace, or both, are in thermal contact with the alkali vapor cell (904, 1503) such that when current is passed through the electrically conductive element, thereby producing heat, the heat is transferred to the alkali vapor cell (904, 1503), characterised in that at least one of the top trace and bottom trace has a filamentary structure comprising a plurality of electrically insulated sub-traces configured to minimize magnetic field fluctuation in a predetermined volume that includes at least a portion of the assembly. an alkali vapor cell (904, 1503); at least one illumination source (902, 1501) configured to emit light when activated, the emitted light having a first predetermined range of wavelengths; a light collector capable of collecting light in the first predetermined range of wavelengths; and a plurality of optical elements arranged such that (a) light emitted from the at least one illumination source is directed to the alkali vapor cell, and (b) light emerging from the alkali vapor cell is directed to the light collector; a generally planar electrical insulator (901, 1507) having a top and a bottom, the top and the bottom being opposed to one another, wherein at least one of the alkali vapor cell (904, 1503), illumination source (902, 1501), or an optical element is supported upon the generally planar electrical insulator; a top trace on the top of the insulator (901, 1507); a bottom trace on the bottom of the insulator (901, 1507); and a through trace, the insulator (901, 1507) defining a via from the top to the bottom, the through trace contacting both the top trace and the bottom trace and passing through the via so that the top trace, bottom trace and through trace form a single electrically conductive element; wherein the top trace and the bottom trace are congruent so that a current along the single electrically conductive element tends to create a self-cancelling magnetic field; and wherein the top trace, or the bottom trace, or both, are in thermal contact with the alkali vapor cell (904, 1503) such that when current is passed through the electrically conductive element, thereby producing heat, the heat is transferred to the alkali vapor cell (904, 1503), characterised in that at least one of the top trace and bottom trace has a filamentary structure comprising a plurality of electrically insulated sub-traces configured to minimize magnetic field fluctuation in a predetermined volume that includes at least a portion of the assembly.