Interaction of relativistic H sup minus ions with thin foils

Technical Report · Sat Sep 01 04:00:00 EDT 1990

DOI:https://doi.org/10.2172/6509741· OSTI ID:6509741

Mohagheghi, A H

The response of relativistic H{sup {minus}} ions to thin carbon foils was investigated for beam energies ranging from 226 MeV to 800 MeV. For the foil thicknesses we have 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 of 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 < n < 17, at beam energies of 581 MeV and 800 MeV. The yield of low-lying states were measured by Doppler tuning a Nd:YAG laser to excite transitions to a Rydberg state which was then field-ionized and detected. A simple model is developed to fit the yield of each state as a function of foil thickness. The simple model is successful in predicting the general features of the yield data. However, the data are suggestive of a more complex structure in the yield curves. The yield of a given state depends strongly on the foil thickness, demonstrating that the excited states are formed during the passage of the ions through a foil. The optimum thickness to produce a given state increases with the principal quantum number of the state suggesting an excitation process which is at least pratially 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. The distributions of the excited states and their dependence on foil thickness are discussed.

• Research Organization: Los Alamos National Lab., NM (USA)
• Sponsoring Organization: DOE/ER
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 6509741
• Report Number(s): LA-11925-T; ON: DE91000514
• Country of Publication: United States
• Language: English

Related Subjects

656003* -- Condensed Matter Physics-- Interactions between Beams &amp; Condensed Matter-- (1987-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANIONS
BEAMS
CARBON
CHARGED PARTICLES
COLLISIONS
CROSS SECTIONS
DATA ACQUISITION SYSTEMS
DIFFERENTIAL EQUATIONS
ELECTRON DETACHMENT
ELECTRON SPECTROMETERS
ELEMENTS
ENERGY LEVELS
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
EQUATIONS
EQUATIONS OF MOTION
EXCITED STATES
FILMS
FOILS
HYDROGEN 1 MINUS BEAMS
HYDROGEN IONS
HYDROGEN IONS 1 MINUS
ION BEAMS
ION COLLISIONS
IONIZATION
IONS
LASERS
MEASURING INSTRUMENTS
MOMENTUM TRANSFER
MONTE CARLO METHOD
NEODYMIUM LASERS
NONMETALS
PARTIAL DIFFERENTIAL EQUATIONS
PHOTOIONIZATION
RELATIVISTIC RANGE
RYDBERG STATES
SOLID STATE LASERS
SPECTROMETERS
THIN FILMS