DENSITY DEPENDENCE OF RECOMBINATION IN THE ELECTRON COOLER OF CRYRING

The electron-ion recombination rates of Ne10+ and D+ have been measured as a function of relative energy and electron density. We found a strong enhancement of e-Ne10+ recombination over expected radiative recombination rates below 1 meV relative energies, reaching a factor of 4 close to zero relative energy. Remarkably, the measured rate coefficients decrease as a function of electron density for both systems. Studies of recombination of D+ indicate that this density dependence may be due to temperature variations of the electron beam with the electron density.