Determination of beam orientation of optical diagnostics of excited 200-MeV hydrogen atoms resulting from photodetachment of H(-)ions

Nondestructive diagnostic techniques to determine beam direction of 200-MeV H atoms are analyzed. These methods are based on excited hydrogen atoms in n=2 and n=3 levels due to photodetachment of H(-) ions. An e-beam driven ArF laser can produce H*(2s) atoms for LRF by photoneutralizing H(-) ions in a quantity comparable to that of a gas cell if longer pulse hot cathode e-beam drivers are developed. Observation of fluorescence from spontaneous decay of H*(2p) or induced decay of H*(2s) can be readily used to indicate beam orientation with 40 microrad accuracy. Measurements of minute Doppler shifts of this Lyman-alpha radiation by a spectrograph could in principle resolve beam direction to within 2.8 microrad. For schemes requiring n=3 hydrogen atoms, an Xe laser can produce H*(3s) or H*(3p) atoms in quantities larger than any produced previously.