VUV SPECTROSCOPY OF MAGNETICALLY TRAPPED ATOMIC-HYDROGEN

We discuss the experimental and theoretical aspects of absorption spec troscopy of cold atomic hydrogen gas in a magnetostatic trap using a p ulsed narrow-band source (bandwidth almost-equal-to 100 MHz) at the Ly man-alpha wavelength (121.6 nm). A careful analysis of the measured ab sorption spectra enables us to determine non-destructively the tempera ture and the density of the trapped gas. The development of this diagn ostic technique is important for future attempts to reach Bose-Einstei n condensation in trapped atomic hydrogen.