ISSN:
1089-7623
Quelle:
AIP Digital Archive
Thema:
Physik
,
Elektrotechnik, Elektronik, Nachrichtentechnik
Notizen:
With the increasing duration of space flights, the development of a permanent facility in space, and the increasing use of ground-based hyperthermal atomic oxygen sources there is a need for a simple instrument to provide long-term monitoring of the beam flux. Such an instrument can also be used as a diagnostic tool to investigate the material degradation process. Reliance on models of the upper atmosphere to determine the fluence of atomic oxygen is not only necessarily complex but also imprecise due to the strong dependence of oxygen concentration on day/night, latitude, and solar activity. Mass spectroscopy, the traditional method for determining the gas phase species densities at low pressure, is not only expensive but is limited in the area that it can monitor as well as subject to effects of material degradation. Our group has developed a simple and inexpensive dosimeter to measure the atomic oxygen fluence via the change in resistance as the sensor element is gradually oxidized. The sensors consist of thin-film circuit elements of selected material deposited on a suitable substrate. Four-point resistance measurements are used to monitor the change in sensor resistance with respect to time. Results obtained from silver and carbon dosimeters flown on STS-46 (CONCAP-II-01) indicate that such sensors are sensitive enough to monitor the diurnal variations in atomic oxygen distribution and sufficiently durable to last the lifetime of a mission. © 1997 American Institute of Physics.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1063/1.1148322
Permalink
