APPLICATIONS OF NUCLEAR TRACK DETECTORS IN SPACE RADIATION DOSIMETRY.

Over the past twenty years, the radiation environment of manned spacecraft has been measured by a variety of detector types. The high-LET (linear energy transfer) spectrum produced by HZE particles has been measured by plastic nuclear track detectors which included different combinations of CR-39, polycarbonate and cellulose nitrate sheets. These detectors are lightweight, compact, and have provided an effective means of measuring the high LET on all the space shuttle flights to date, including Spacelab-1, as well as the past missions of Apollo and the Skylab series. For low LET, absorbed dose and dose rates as a function of such parameters as inclination, altitude, spacecraft type and shielding have been measured with thermoluminescent detectors (TLD's). For low Earth-orbit missions the dose encountered was found to be strongly altitude-dependent, with a smaller dependence on orbit inclination. This paper presents radiation data gathered on the last several space shuttle flights and discusses further experiments which are being planned.