The absolute cross section for the reactions of deuterons on beryllium which produce titrium and ${\mathrm{Be}}^{10}$ have been measured up to energies of 17 to 20 million electron volts. Data of Dejong, Endt, and Simons show no threshold which is as expected for exothermic ($d, p$) and ($d, t$) processes. For the reaction producing ${\mathrm{Be}}^{10}$, which is equivalent to the introduction of a neutron into the beryllium nucleus by the bombarding deuteron, the cross section rises to a peak value of about 0.34 barn, at about 4 Mev. It then falls almost linearly to the low value of 0.08 barn at 20 Mev. There are evidences of fine structure in the curve but it is possible that these are not really significant. The reaction producing tritium rises to a peak value of about 0.23 barn at about 5 Mev and then falls to a low value of about 0.03 barn at 13 Mev. The reaction cross section appears to remain essentially constant at this low value although it may rise slightly as the energy is raised to about 20 Mev. A new reaction producing tritium begins at 17.47 Mev, namely one which produces both tritium and ${\mathrm{Be}}^7$ simultaneously. This corresponds to the ejection of both a triton and a neutron as a result of the deuteron ${\mathrm{Be}}^9$ collision. This cross section rises from zero at the threshold linearly to a value of 8×${10}^{-5\mathrm{}}$ barn at 21.5 Mev.

• Received 1 March 1955

DOI:https://doi.org/10.1103/PhysRev.100.799