SEARCH FOR PHOTODEUTERIUM FROM COPPER

Copper foil samples were irradiated with bremsstrahlung of 24-, 30-, and 40-Mev peak energy, and production of deuterium by the ( gamma ,d) reaction investigated. After irradiation, gas released from the samples was introduced into an omegatron mass spectrometer and the ion currents HHD/sup +/ and HH/sup +/ measured. The sensitivity of the detection was sufficient to use the amount of deuterium in natural hydrogen as calibration. No HHD/sup +/ was observed after irradiation at 24 and 30 Mev and the ratio of deuterium to hydrogen in the irradiated samples was estimated to be less than 0.0016 and 0.00014, respectively. At 40 Mev the ratio was measured to be approximately 0.0009. The ratio of deuterium to hydrogen expected on an evaporation theory was calculated for several level density formulas. The predicted values are much greater than the observed deuterium to hydrogen ratio. It is concluded that deuterons are not evaporated from copper at these photon energies. The direct photointeraction pickup process of Madsen and Henley is estimated to predict a ratio of deuterium to hydrogen of 0.0012 at 40 Mev and 0.0003 at 30 Mev for relatively high residual nucleus excitations. Such predictions seem consistent with the experimental results. (auth)