Electron Ionization Cross Sections.
Annual progress rept. 1 Aug 68-1 Aug 69,
MASSACHUSETTS INST OF TECH CAMBRIDGE PARTICLE OPTICS LAB
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A new carbon beam source which can be operated at high temperature was designed and built for the study of ionization cross sections of atomic carbon. The power required to operate at 2400K, about 165 watts, is close to the expected value the power increases as T to the 5th power. Problems were experienced with the ion trap, which itself emitted ions from hot internal surfaces. A redesigned trap reduced the stray electron current to a comparable value. The detection efficiency and count loss in the electron multiplier was calculated by use of generating functions and compared with experimental results. Fragmentation has been studied using time-of-flight techniques in the frequency domain. The experiments show that fragmentation is responsible for less than 10 of total ion current. The relative ionization cross sections for C1, C2, and C3 have been measured using a chopped beam method. Absolute values were then calculated. Author
- Test Facilities, Equipment and Methods
- Atomic and Molecular Physics and Spectroscopy