Measurements of In Situ Production of Carbon-14 in Silicon Dioxide Production Rates and Cross-sections

Abstract

<p>The development of a technique for the extraction of ¹⁴c extraction technique and the ¹⁴c Accelerator Mass Spectrometer detection technique were applied to the measurements reported in this work. Samples of quartz chips were irradiated with neutrons produced by a 20 MeV tritium beam interacting with a deuterated Ti foil target. This irradiation permitted the first measurement of the ¹⁶o(n,2pn)¹⁴c cross section at 35 MeV for which a value of 16±3 mb was found. Two stacks of quartz plates were irradiated with 63 MeV protons. The measurement of the ¹⁶o(p,3p)¹⁴c cross section at several energies below 63 MeV are presented. The ¹⁴c in-situ produced was measured in seven obsidian rock samples. In four cases the values obtained agree with the calculated production rate of 0.19±0.05 atoms Kg⁻¹ min⁻¹ at 46º geomagnetic latitude and 640 g cm⁻².</p>