Interaction Of Proton Beam Research Articles

Fine structure measurements at the n=2 state of hydrogen with the quantum beat method

Quantum beats were observed in Lyman α emission (1216 Å) from hydrogen atoms formed by beam-foil interaction of proton beams. In the zero-field case, the P 1 2 − P 3 2 fine structure separation (10 969 GHz) could be easily resolved and relative excitation cross sections for magnetic substrates of the 2P level were derived from modulation amplitudes in the energy range from 50 to 270 keV. Applying a transverse magnetic field, coherent decay of 2P and 2S states was observed. Fourier transform of the measured intensity versus time curve was obtained showing three lines in coincidence with the calculated frequency spectrum. The possibility of deterining the S 1 2 − P 1 2 level separation (Lamb shift) from frequency ratios with great accuracy is discussed.

The proton scattering microscope.

Recent experiments on the interaction of proton beams with solids have shown that the regular variations of intensity in the spatial distribution of the scattered beam was dependent on the regular nature of the crystalline lattice. This phenomenon has been exploited in an apparatus which may be applied to the orientation and examination of single crystals and thin crystalline films. In the proton scattering microscope to be described, a beam of protons is directed on to the crystal under investigation and the scattered beam is observed directly on a fluorescent screen.