In vitro exposure apparatus for ELF magnetic fields.
For in vitro studies on the effect of extremely low frequency (ELF) magnetic field exposures in different laboratories, a programmable, high precision exposure system enabling blinded exposures has been developed and fully characterized. It is based on two shielded 4 coil systems that fit inside a commercial incubator. The volume of uniform B field exposure with 1% field tolerance is 50% larger compared to a Merrit 4 coil system with the same coil volume. The uncertainties for the applied magnetic fields have been specified to be less than 4%. The computer controlled apparatus allows signal waveforms that are composed of several harmonics, blind protocols, monitoring of exposure and environmental conditions and the application of B fields up to 3.6 mT root-mean-square amplitude. Sources of artifacts have been characterized: sham isolation >43 dB, parasitic incident E fields <1 V/m, no recognizable temperature differences in the media for exposure or sham state, and vibrations of the mechanically decoupled dish holder <0.1 m/s(2) (= 0.01 g), which is only twice the sham acceleration background level produced by the incubator and fan vibrations.
Schuderer
Jürgen
J
Foundation for Research on Information Technologies in Society (IT'IS), Integrated Systems Laboratory IIS, Swiss Federal Institute of Technology (ETH), Zurich, Switzerland. jschuder@itis.ethz.ch
Oesch
Walter
W
Felber
Norbert
N
Spät
Denis
D
Kuster
Niels
N
D018929:Cell Culture Techniques / Q000295:instrumentation* / Q000379:methods; D004574:Electromagnetic Fields; D055590:Electromagnetic Phenomena / Q000295:instrumentation* / Q000379:methods; D004780:Environment, Controlled; D004867:Equipment Design; D019544:Equipment Failure Analysis; D011829:Radiation Dosage; D011874:Radiometry / Q000295:instrumentation*; D014159:Transducers