FIG. 1.

Optical imaging setup within a water-cooled Florida-Bitter electromagnet. The magnetic field strength (0–30 T) and the magnetic field gradient depend on the value of the electrical current through the magnet coil and the vertical position within the magnet. The light beam of a light-emitting diode (LED, wavelength 630 nm) is collimated using a lens, guided through the sample cuvette by aluminum mirrors, and focused on a charge-coupled device (CCD) camera with an imaging lens [focal length 250 mm (Paramecium) or 80 mm (Euglena)] and a zoom lens. (Color graphics available online at www.liebertonline.com/ast)