AVERAGE KINETIC-ENERGY OF ATOMS IN A SOLID MEASURED WITH RESONANT NUCLEAR-REACTIONS

Solid neon samples at 8 +/- 2 K and under vapor pressure were used to measure yield curves of the 272-keV nuclear resonance in the Ne-21(p,g amma)Na-22 reaction. The Doppler broadening of the narrow resonance du e to target atom motion was determined with very good beam energy reso lution. The average kinetic energy of single neon atoms in the solid d ue to their motion in the beam direction was E-kin,E-z = 1.06 +/- 0.2 meV (corresponding to an average kinetic energy of E-kin/k = 37 +/- 7 K). This value is in good agreement with published values obtained fro m neutron Compton scattering and from path-integral Monte Carlo calcul ations. [S0163-1829(98)07142-2].