Elastic electron-neutral interaction measurements in neon at ultralow energies

The cross section ${\sigma }_{\mathrm{MT}}$ for the elastic momentum transfer of electrons with neon atoms in the electron energy range $3\times {10}^{-3\mathrm{}}\le u\left(\mathrm{eV}\right)\le 5\times {10}^{-1\mathrm{}}$ has been deduced from measurements of the microwave absorptivity of a transient cryogenic afterglow plasma. A least-squares fit of our experimental data by the modified effective range formula gives a zero-energy scattering length of $(0.24\mathrm{}\pm 0.015)a_0$, where $a_0$ is the Bohr radius.