Doctoral Dissertations


"Double Differential Cross Sections (DDCS) were measured for single ionization of H₂ by 75 keV proton (p) impact as a function of the projectile scattering angle (θp) for a fixed energy loss (ΔE) for two different target-collimating slit distances, which determined the width of the projectile wave packet (Δx). In one case Δx was larger than the inter-nuclear separation of the H₂ molecule (coherent projectile beam), while for the other case it was much smaller than the inter-nuclear separation (incoherent projectile beam). A Young type interference pattern was observed in the coherent data, but this was not present in the incoherent data. The results imply that the projectile coherence can have a clear effect on measured cross sections and that the experimental beam preparation must be incorporated in the theoretical treatment. Moreover Single Differential Cross Section (SDCS) were measured for single electron capture by 75 keV proton impact on H₂, and here, too, a similar effect was observed. Furthermore SDCS for single electron capture by 25 keV proton impact on H₂ and He targets also revealed interference structures, qualitatively different from the Young type interference structures seen at 75 keV proton energy. Structures for the Helium target imply that the effect of projectile coherence can be present for atomic targets as well.

In a previous experiment, it has been shown that these Young type interference structures are to a large extent independent of ΔE. This suggests that they should also be independent of the process occurring in the collision. To test this DDCS were measured for dissociative ionization for 75 keV proton impact on H₂ as a function of θp for four ΔE values. Additional structures compared to non dissociative ionization were observed"--Abstract, page iv.


Schulz, Michael, 1959-

Committee Member(s)

Peacher, Jerry
Samaranayake, V. A.
Madison, Don H.
Waddill, George Daniel



Degree Name

Ph. D. in Physics


Missouri University of Science and Technology

Publication Date

Fall 2011

Journal article titles appearing in thesis/dissertation

  • Manipulating atomic fragmentation processes by controlling the projectile coherence
  • Scattering-angle dependence of doubly differential cross sections for fragmentation of H₂ by proton impact


viii, 64 pages

Note about bibliography

Includes bibliographical references.


© 2011 Kisra Nayomal Egodapitiya, All rights reserved.

Document Type

Dissertation - Restricted Access

File Type




Subject Headings

Collisions (Nuclear physics)
Nuclear fragmentation
Particles (Nuclear physics)

Thesis Number

T 9895

Print OCLC #


Electronic OCLC #


Link to Catalog Record

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