Interaction of relativistic H sup minus ions with thin foils

Journal Article · Fri Feb 01 04:00:00 EST 1991 · Physical Review, A; (USA)

DOI:https://doi.org/10.1103/PhysRevA.43.1345· OSTI ID:5622212

Mohagheghi, A H; Bryant, H C; Harris, P G; Reeder, R A; Sharifian, H; Tang, C Y; Tootoonchi, H ^[1]; Quick, C R; Cohen, S ^[2]; Smith, W W ^[3]; Stewart, J E ^[4]

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1. University of New Mexico, Albuquerque, New Mexico 87131 (US)
2. Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (USA)
3. University of Connecticut, Storrs, Connecticut 06268 (USA)
4. Western Washington University, Bellingham, Washington 98225 (USA)

The response of relativistic H{sup {minus}} ions to thin carbon foils was investigated for beam energies ranging from 226 to 800 MeV. For the foil thicknesses studied, ranging from 15 to 300 {mu}g/cm{sup 2}, an appreciable fraction of the H{sup {minus}} beam survives intact, some H{sup {minus}} ions are stripped down to protons, and the remainder is distributed over the states of H{sup 0}. This experiment is different from the low-energy studies in that the projectile velocity is comparable to the speed of light, leading to an interaction time typically less than a femtosecond. The present results challenge the theoretical understanding of the interaction mechanisms. An electron spectrometer was used to selectively field ionize the Rydberg states 9{lt}{ital n}{lt}17 at beam energies of 581 and 800 MeV. The yield of low-lying states was measured by Doppler tuning a Nd:YAG (where YAG represents yttrium aluminum garnet) laser to excite transitions to a Rydberg state that was then field ionized and detected. Data are presented for production of {ital n}=2,3 at 226 MeV, {ital n}=2,3 at 500 MeV, {ital n}=2,3,4 at 581 MeV, {ital n}=2 at 716 MeV, and {ital n}=1,2,3,4,5 at 800 MeV. A simple model is developed to fit the yield of each state as a function of foil thickness. Although the simple model is successful in predicting the general features, the data are suggestive of a more complex structure, in the yield of a state as a function of the foil thickness. The optimum thickness to produce a given state increases with the principal quantum number of the state, suggesting an excitation process that is at least partially stepwise. The results of a Monte Carlo simulation are compared with the experimental data to estimate the distribution of the excited states coming out of a foil.

• OSTI ID: 5622212
• Journal Information: Physical Review, A; (USA), Journal Name: Physical Review, A; (USA) Vol. 43:3; ISSN 1050-2947; ISSN PLRAA
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ANIONS
CARBON
CHARGED PARTICLES
ELEMENTS
ENERGY LEVELS
ENERGY RANGE
EXCITED STATES
FOILS
HYDROGEN IONS
HYDROGEN IONS 1 MINUS
ION SPECTROSCOPY
IONS
MEV RANGE
MEV RANGE 100-1000
MONTE CARLO METHOD
NONMETALS
RYDBERG STATES
SPECTROSCOPY