Radiation Damage in Ice at Low Temperatures Studied by Proton Channelling

• Published in: Journal of Glaciology
• Main Authors: Golecki, I., Jaccard, C.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 1978
• Subjects: Earth-Surface Processes; Journal of Glaciology
• Online Access: http://dx.doi.org/10.1017/s0022143000033451; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000033451

Abstract 100 keV protons with fluxes between 3 × 10 15 and 3 × 10 16 m -2 s -1 and in doses up to 4 × 10 20 m -2 have been used in ice between - 191°C and -87°C to create damage and to analyse it. The Rutherford backscattering minimum yield along the c-axis (about 0.05 in good monocrystals) increases up to unity with the dose, according to a function which can be scaled by a critical dose depending mainly on temperature (Arrhenius law with activation enthalpy of 0.17 ± 0.04 eV above -185°C). Higher flux produces more damage above -180°C, but less below. A beam in a random direction is more efficient below - 180°C, but less at higher temperature than an aligned beam. Beam-induced reordering is observed at definite temperatures and doses. The damage is shown to be due to energy loss by electronic excitations, which decay and produce disordered molecule clusters, mainly by incoherent aggregation of vacancies and interstitials.