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Title: Interaction of relativistic H sup minus ions with thin foils

Abstract

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 amore » 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.« less

Authors:
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
DOE/ER
OSTI Identifier:
6509741
Report Number(s):
LA-11925-T
ON: DE91000514; TRN: 90-032399
DOE Contract Number:  
W-7405-ENG-36
Resource Type:
Technical Report
Resource Relation:
Other Information: Thesis (Ph.D.). Thesis submitted to Univ. of New Mexico, Albuquerque
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; FOILS; ION COLLISIONS; CARBON; CROSS SECTIONS; DATA ACQUISITION SYSTEMS; ELECTRON DETACHMENT; ELECTRON SPECTROMETERS; ENERGY-LEVEL TRANSITIONS; EQUATIONS OF MOTION; EXCITED STATES; HYDROGEN 1 MINUS BEAMS; HYDROGEN IONS 1 MINUS; MOMENTUM TRANSFER; MONTE CARLO METHOD; NEODYMIUM LASERS; PHOTOIONIZATION; RELATIVISTIC RANGE; RYDBERG STATES; THIN FILMS; ANIONS; BEAMS; CHARGED PARTICLES; COLLISIONS; DIFFERENTIAL EQUATIONS; ELEMENTS; ENERGY LEVELS; ENERGY RANGE; EQUATIONS; FILMS; HYDROGEN IONS; ION BEAMS; IONIZATION; IONS; LASERS; MEASURING INSTRUMENTS; NONMETALS; PARTIAL DIFFERENTIAL EQUATIONS; SOLID STATE LASERS; SPECTROMETERS; 656003* - Condensed Matter Physics- Interactions between Beams & Condensed Matter- (1987-)

Citation Formats

Mohagheghi, A H. Interaction of relativistic H sup minus ions with thin foils. United States: N. p., 1990. Web. doi:10.2172/6509741.
Mohagheghi, A H. Interaction of relativistic H sup minus ions with thin foils. United States. https://doi.org/10.2172/6509741
Mohagheghi, A H. 1990. "Interaction of relativistic H sup minus ions with thin foils". United States. https://doi.org/10.2172/6509741. https://www.osti.gov/servlets/purl/6509741.
@article{osti_6509741,
title = {Interaction of relativistic H sup minus ions with thin foils},
author = {Mohagheghi, A H},
abstractNote = {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.},
doi = {10.2172/6509741},
url = {https://www.osti.gov/biblio/6509741}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Sat Sep 01 00:00:00 EDT 1990},
month = {Sat Sep 01 00:00:00 EDT 1990}
}